Rookie MTB questions!

[Dr_Alex_Harrison]

Sorry in advance! Even 1 answer is appreciated if you’ve got it handy

What are the best MTB forum(s)? Preferably with XC included. (ie not just a DH forum)

Is one of them worth joining, given below info?

• I’m active on TR and ST & prefer to limit number of forums.
• @michelleihowe and I now own two used 2020 Scott Sparks w/ AXS
• The last MTB I owned was like this but 15 yrs older
• Experienced w/ road, track, tri, gravel.
• I do all mechanic work. Beginner/enthusiast.
• Cervelo 2017 T4, 2014 P5, 2018 S5, and 2019 Cannondale SuperSix Evo HiMod.
• Just sold our CAADX 105 gravel bikes. ie. I’ve seen disc brakes, but not worked on.

I plan to do all mechanic work.

Got answers? UPDATE: Fully answered questions have been moved to bottom.

1. Assuming I have all tools to do all work on road bikes, what are the first tools/items I need to get to work on these MTBs?

2. Anything else I need to work on our MTBs that might be more “down the road?”

3. Do CR2032 discharge if they come into contact with each other or other metal objects in a bike bag?

4. I pumped tires to 55psi on my bike just to see what the stiffest “feel” I could get out of the bike would be, with the shocks locked out, found traction was amazing, and played with how hard I could brake without losing traction. Answer: very very hard. Rode for <5min. 20min later, I hear the front tire explode. Big tear in the inner fabric lining of tire, and gaping hole in the tread that I could stick 2 fingers through. Why did this happen?

5. What are your favorite full-fingered gloves for hot temperature days?

6. Same glove question but for women, if different.

7. My personal riding experience includes riding DH @ Whistler DH on a hardtail 15 yrs ago. My bike looked like this. It was in rough shape after a week of riding at Whistler. Are there any considerations I should be aware of so that I don’t damage components of my expensive XC bike if I’m 210 pounds and tend to ride aggressively??

8. Should heavier riders run wider tires as in road? Is there a good resource for tire width and PSI by body weight and riding style?

9. The plastic presta valve caps are still on a couple of the wheels? I throw these out typically with regard to road cycling… is there a reason I should keep them for MTB?

10. My wife’s bike came with 160mm front and rear disc brakes. Mine has 160mm rear and 180mm front. What do I need to do to change hers to 180 or mine to 160, so that there is immediate wheel cross-compatibility?

Answered:

1. What is a shock pump and why do I need it? (I notice the valve on the rear shock).

2. How long do AXS rear mech batteries last on a single charge? Similar to di2?

3. How long do AXS dropper post batteries last on a single charge?

4. How long do the CR2032 batteries in the shifters and dropper post switch tend to last?

5. Do you carry spare CR2032 batteries with you in a kit? Multiple? If so, do you need to wrap them in anything to prevent discharge?

6. The tires say 35-60psi. Do you really run them that high?

7. Why are the presta valves are much harder to unscrew to open for inflation compared to our road bikes.strong text

8. Most importantly, how strongly will we prevent making friends on the trail if we wear nothing but roadie apparel? Tri apparel??? Convince me that I need MTB apparel. We live in a motorhome so space is limited.

[Pbase]

Wow! Lots of questions! Welcome to mtb! Those are awesome starter bikes.

First, for some simple stuff. Tubeless, right?

[Pbase]

Shock pump - a special handheld pump that puts pressure in the shock and has a gauge on it. Check out the manual and see how much sag your bike calls for. For example, it it calls for 1/4 of the travel sag, pump it up, and then sit on the bike while holding onto a wall and see how far the bike “sags” into the shock travel. If you have an o-ring on the shock, that helps. This will change from shock to shock and based on rider weight.

Bonus, you will also use this pump for your fork.

Next you’ll have to dial the rebound on both the shock and fork. That’s a whole additional conversation.

[Pbase]

AXS batteries last pretty long. There is an app you can download and connect to them to see how full they are.

The shifter batteries last a REALLY long time. I do keep one in my pack.

[Juicetin]

Definitely run tubeless. I am like 18 psi in my tubeless tires and I weigh 150 lbs. Tire width and tread patterns kinda depend on the terrain, and rider opinion as well.
Haven’t been on the forum in a while, but when I’ve had questions in the past I’ve gone on mtbr forums and had success getting info.
I wear roadie gear on the mtb every time. I really don’t see how it’s ever beneficial to wear baggy clothing and I’m cool not making friends with someone if they judge my riding outfit:)

[Juicetin]

Regarding disc brakes, they are super easy to work on but I remember the first time bleeding being kinda intimidating but it’s really pretty easy to wrap your brain around once you’ve got a bleed kit and understand your specific model. Regarding rotors and size I imagine it wouldn’t be super complicated to change out but depends on the specific caliper mounts.

[Rosscopeco]

@Dr_Alex_Harrison

• I’m active on TR and ST & prefer to limit number of forums.
• @michelleihowe and I now own two used 2020 Scott Sparks w/ AXS

There’s plenty of MTB peeps on here. Quite a few who ride the Scott Spark as well, myself included.

@Dr_Alex_Harrison

Assuming I have all tools to do all work on road bikes, what are the first tools/items I need to get to work on these MTBs?

If you’ve already got tools for road bikes you should be good for most things.
My Spark has a load of Torx heads along with the usual allen heads. Make sure you’ve got a torque wrench and add checking the suspension linkages to your routine.

@Dr_Alex_Harrison

What is a shock pump and why do I need it? (I notice the valve on the rear shock).

There are recommended pressures to run the suspension at based on your weight. You’ll need a shock pump to adjust the front and rear suspension. (The Fox website has instructional vids from memory).

@Dr_Alex_Harrison

Anything else I need to work on our MTBs that might be more “down the road?

Derailer hanger alignment tool. Spoke tension tool. Brake bleed kit (not tried this yet on a bicycle).

@Dr_Alex_Harrison

The tires say 35-60psi. Do you really run them that high?

Nope. I’m around 75kgs and hover around the 20-22psi mark(tubeless). At your weight you’ll probably want a little more to stop your rims getting beat up.

@Dr_Alex_Harrison

The plastic presta valve caps are still on a couple of the wheels? I throw these out typically with regard to road cycling… is there a reason I should keep them for MTB?

I leave mine on to protect the valve core. Single track can throw up some nasty things into your frame and wheels.

@Dr_Alex_Harrison

Most importantly , how strongly will we prevent making friends on the trail if we wear nothing but roadie apparel? Tri apparel??? Convince me that I need MTB apparel. We live in a motorhome so space is limited.

Most people don’t care.
Around my way all the XC crowd tend to wear full Lycra anyway so it has more to do with what you’re doing on the bike.
A good MTB helmet will offer better coverage. Baggies and a long sleeve MTB jersey is great if you’re stuffing around and can save you from gravel rash.
I say ride in your road kit and adjust to suit as you decide what you want to do on the bike.

Have fun on your new toys. They’re good bikes.

[Pbase]

I asked about tubeless because it answers a few of your questions. I’m going to assume yes, tubeless. You will run much lower PSI if you’re on tubeless. It will depend on the size of the tires, but at 210, I’m guessing around 30ish.

If you have tubeless, you’ll need something to seal the tubeless tires to the rim. There are severa options out there that involve air compression.

You’ll also need sealant in the tires. I like Orange Seal, but there are several brands. Sealant dries up, so you need to replace it.

That sealant gets in the valve cores and makes them sticky. That’s probably why you’re having trouble unscrewing the prestas.

I’d recommend some form of bacon strip tool for when your sealant doesn’t seal the tire. I also keep a piece of duct tape in my pack in case of a fatal tear.

A chain breaker and an extra link.

If you use CO2, you’ll need bigger or more than one canister. I prefer to carry a pump, but be warned, you’ll get a workout using one.

Plenty of people use road helmets, but I like to have an mtb helmet for the added protection.

Gloves are personal, but I like them thin and with minimal padding or armor. My personal favorite full finger for XC is the Dakine Boundary.

If you plan to ride flat pedals, the most popular shoe, by far, at least in my crowd, is the Five Ten Freerider.

I tend to scrape trees, so while I live where it’s really hot, I still prefer light long sleeve jerseys. Nothing wrong with wearing a road jersey though. Just drop anyone who gives you crap about it!

[Dr_Alex_Harrison]

@Pbase

Welcome to mtb!

Thank you!

@Pbase

Tubeless, right?

Yes.

Purchased a cannister inflator thing to help seat tires because that was a bear on our gravel bikes!

@Juicetin

I’m cool not making friends with someone if they judge my riding outfit:)

Cool. We can be friends then.

@Juicetin

Regarding rotors and size I imagine it wouldn’t be super complicated to change out

Looks like different bolt pattern. Modifying wheel necessary?? Or do they make 180mm rotors that fit on my wife’s bolt pattern?
Mine:

Hers:

@Juicetin

but depends on the specific caliper mounts.

I already figured out how to install these by trial and error since the bikes came partially unassembled. Phew!

@Rosscopeco

add checking the suspension linkages to your routine.

You referring to the T27 bolts around the frame articulation points near the rear shock?

@Rosscopeco

Derailer hanger alignment tool. Spoke tension tool.

Would these be any different than those of a road bike? If not, I have both. Good thinking

@Rosscopeco

Brake bleed kit (not tried this yet on a bicycle).

Noted! How often does this need to be done? What is the purpose of doing so, or indicator that it needs doing?

@Pbase

That sealant gets in the valve cores and makes them sticky. That’s probably why you’re having trouble unscrewing the prestas.

Got it. Thought that might be the case. I’ve got sealant. How do I know when to replace it / add it? Do I need to take the tire off and clean the inside before re-applying / adding sealant?

@Pbase

bacon strip tool

That’s a new one for me. Recommendations??

@Pbase

I also keep a piece of duct tape in my pack in case of a fatal tear.

A chain breaker and an extra link.

If you use CO2, you’ll need bigger or more than one canister. I prefer to carry a pump, but be warned, you’ll get a workout using one.

As much touring / long-distance riding as my wife drags me through on the road, this is all standard issue on our road bike bags.

@pbase, all fantastic info, thank you!

[Dr_Alex_Harrison]

@Rosscopeco

I leave mine on to protect the valve core. Single track can throw up some nasty things into your frame and wheels.

Good to know!

@Rosscopeco

I say ride in your road kit and adjust to suit as you decide what you want to do on the bike.

Cool.

[Pbase]

@Dr_Alex_Harrison

How do I know when to replace it / add it? Do I need to take the tire off and clean the inside before re-applying / adding sealant?

The old school way is to push the tire off the rim and look inside. I prefer to just remove the valve core and use the stick that comes with Orange Seal (or a toothpick) to see how deep the liquid is inside (think of this like sticking a toothpick in cake to see how much comes out). If it’s just a little low, I’ll usually just add some through the tube attached to the bottle. If it’s dry, I’ll remove the tire and clean it out before re-applying.

For tire plugs (bacon), here’s a cheap and small one.

Amazon.com: yinat Manual Tubeless Tire Repair Kit MTB Bacon Strips Plus...

A nicer one
https://www.amazon.com/dp/B07MH9K4NR/ref=dp_iou_view_product?ie=UTF8&psc=1

The cool new kid on the block (but also quite large)
https://www.amazon.com/Stans-Dart-Tubeless-Repair-Darts/dp/B07ZG9N33Y/ref=sr_1_2?crid=26PFG68EQTAH0&dchild=1&keywords=stans%2Bdart%2Btubeless%2Btire%2Brepair%2Btool&qid=1617582674&s=sporting-goods&sprefix=Stans%2Bdart%2Csporting%2C191&sr=1-2&th=1&psc=1

[Dr_Alex_Harrison]

Thank you!

[splash]

@Dr_Alex_Harrison

Looks like different bolt pattern. Modifying wheel necessary?? Or do they make 180mm rotors that fit on my wife’s bolt pattern?

Both of those are centre-lock discs. The bolts you see are decoupling the discs itself from the spyder - don’t take these out. The disc comes off near the hub, look up centre lock.

Changing to a 180mm rotor means you’ll also need an adaptor to move the caliper out to accomondate the larger disc. As you already have two different sized rotors on the bikes (but on the same wheel), you should have one of them already. Regarding caliper, see if they are flat mount or post mount. Many people prefer a larger front rotor as the front brake takes more weight, especially down hill, but you can run two similar ones too, so I wouldn’t worry too much about it.

Talking about brakes (and assuming they are hydraulic) - you might want to bleed them sometime. You’ll need a bleed kit, basically just a few syringes and some stuff. There are two types of brake fluids in use, mineral oil (shimano) and dot 5.1 (sram), you need to use the right one and do not mix them. (If the brakes are a different brand, look up what they use. Magure call theirs “brake blood” and colour it red). Bleeding brakes is easy. You’ll only need to do it when braking feels odd - ie the lever feels “spongy”, or there’s too much travel or not enough. Also maybe if you change altitude by a lot or have the bike upside down for a long time. Look up brake bleeds for your type of brake on youtube.

Forgot to mention, get a stock of brake pads and learn how to change them. In the wrong conditions, you can go through a set in one ride.

[splash]

@Dr_Alex_Harrison

Assuming I have all tools to do all work on road bikes, what are the first tools/items I need to get to work on these MTBs?

Shock pump was already mentioned, but from the other answers I’m assuming you also need tools for tubeless tyres. Get a pump with an air tank to seat tyres, or a small compressor, if you have space for it. Said above, bleed kit for brakes. Stock of sealant for the tyres. If your brakes use mineral oil, you can also get a stock that, but if they use dot 5.1, don’t, because it has a limited shelf life. You might need extra tools for fork and shock service (and dropper post, if you have one), but look up the manuals for them and find out if and what it is.

@Dr_Alex_Harrison

Do CR2032 discharge if they come into contact with each other or other metal objects in a bike bag?

Wouldn’t think so. The two different poles on the battery are the outside housing and the inside housing (see the ring separating them at the bottom). It’s pretty hard to make them touch. I’d still put the batteries into a small plastic bag to carry them, of only to keep them dry. Shifter batteries last a long time though, probably years.

@Dr_Alex_Harrison

I pumped tires to 55psi…

Seems way too high, unless you’re a dirt jumper. Why did the tyre explode? - Shouldn’t happen, evennat those pressures. Were they old tyres? Maybe damaged.

@Dr_Alex_Harrison

Are there any considerations I should be aware of so that I don’t damage components of my expensive XC bike if I’m 210 pounds and tend to ride aggressively??

You might want to learn about and play with suspension settings.

@Dr_Alex_Harrison

Should heavier riders run wider tires as in road? Is there a good resource for tire width and PSI by body weight and riding style?

Tyre choice has more to do with terrain than weight, and riding style. Use suspension settings and tyre pressure to deal with weight differences. Note, there are way more tyre choices out there for mountain bikes than for road bikes, and its normal to swap them if conditions change.

@Dr_Alex_Harrison

The plastic presta valve caps are still on a couple of the wheels? I throw these out typically with regard to road cycling… is there a reason I should keep them for MTB?

Never understood the obsession with taking them off. They protect the valve core, you don’t want that damaged, or you can’t inflate the tyre.

@Dr_Alex_Harrison

Why are the presta valves are much harder to unscrew to open for inflation compared to our road bikes.

Probably have a bit of dried sealant on them. Change the valve cores, if it get too difficult.

Regarding clothing - depends where you ride. MTB clothes are also there to protect you. You don’t want to slide down rocks in lycra or tri kit.

[Rosscopeco]

@splash

You don’t want to slide down rocks in lycra or tri kit.

This.
How good is sandstone! That gentle exfoliating action from even a minor stack.

[commanderobvious]

Welcome to MTB!

4., 7., & 8. Like other have mentioned. Tubeless is the way to go. At 210 and “aggressive” you are going to want to go fairly big IMO. 2.4 reckons are a good start until you get a feel for your preferences. It’s a good tire, fairly fast rolling with decent cornering knobs, but tires might be the most devicive thing in MTB, so don’t be afraid to try something new. For tools, you will want an air compressor or a pump with a compression tube to do tubeless consistently. This takes a bit of practice and like most things, the prep work is the most important part of the job.

10. Looks like you have shimano brakes. You need a shimano 160 to 180 flat mount adaptor and another set of 180mm discs.
    Shimano XTR F180P/P Disc Brake Adaptor for 180mm Rotor, 74mm Caliper, | Worldwide Cyclery

Very easy install. Remove the caliper and place this in between. You’ll notice that you have the same thing on your bike as few XC bikes come stock with 180s. Looks like you are already familiar with the disc install via center lock. Make sure that sucker is tight. It’s the only downside to those

[DaveWh]

Nice list of questions!

@Dr_Alex_Harrison

What are the best MTB forum(s)? Preferably with XC included.

Mountain Bike Reviews Forum

@Dr_Alex_Harrison

• Assuming I have all tools to do all work on road bikes, what are the first tools/items I need to get to work on these MTBs?
• Anything else I need to work on our MTBs that might be more “down the road?”

• Bleed kit for hydraulic brakes if you don’t already have them for your road bikes.

• Tools to do suspension service. I’ve not yet done rear shock, but for fork, you’ll need a big chamferless socket to remove the cap at the top of the fork, and a seal driver to install the new seals.

See the following video for an example of servicing your fork: https://m.youtube.com/watch?v=HVCd_SxBK4c

@Dr_Alex_Harrison

I pumped tires to 55psi on my bike just to see what the stiffest “feel” I could get out of the bike would be

Don’t do this . That’s about 2x what you need.

https://info.silca.cc/silca-professional-pressure-calculator

@Dr_Alex_Harrison

What are your favorite full-fingered gloves for hot temperature days?

I like gloves with gel palm pads. My previous ones were Gore, but they don’t make them any more. I’m currently running these from Pearl Izumi. They’re not as good as my previous Gore ones, but gloves with palm padding are harder to find these days. Seems like all gloves are minimalist for better “bar feel”. Maybe that works for people who do a 5 min downhill run, but it doesn’t work for me 4+ hrs into riding rocky trails in Colorado and Utah.

https://www.amazon.com/PEARL-IZUMI-Elite-Finger-Glove/dp/B07ZPDQ1D1?ref_=ast_sto_dp&th=1&psc=1

You also need to ask what tires you should run. You’ll only get about 100 different answers

[Dr_Alex_Harrison]

Perfect info! Thank you! I’ll get another adapter thing for my wife’s bike and increase her rotor size to 180mm so that in a pinch we can swap wheels or have a spare for races/events.

@commanderobvious

2.4 reckons are a good start

Funny you should mention that. Just bought one to replace my front Ikon that exploded.

@splash

Seems way too high, unless you’re a dirt jumper. Why did the tyre explode? - Shouldn’t happen, evennat those pressures. Were they old tyres? Maybe damaged.

Agreed. No idea! Here’s a picture.

Seems new-ish.

I did brake VERY hard on asphalt a few minutes prior, with the tire at 55 psi. No skid. I’m a big guy with a lot of muscle (too much for any reasonable purpose other than elite bobsledding). I think I might just be “too much” for the tires and I was basically abusing it out of its element. $70 mistake, I think.

Thoughts from the audience?

@commanderobvious

Looks like you have shimano brakes. You need a shimano 160 to 180 flat mount adaptor and another set of 180mm discs.
Shimano XTR F180P/P Disc Brake Adaptor for 180mm Rotor, 74mm Caliper, | Worldwide Cyclery

Just picked one up on amazon! Thank you!

@commanderobvious

Looks like you are already familiar with the disc install via center lock.

Familiar by name and process, via youtube. Haven’t done it yet. Can’t get my tool to fit! Bad tool tolerance? I just purchased the ParkTool lockring adapter on amazon in hopes that it fits. Do I need to remove the thing that the axle goes through to be able to get the tool in??

@DaveWh

I like gloves with gel palm pads.

I think I will too. Very long rides are going to be common I think.

@DaveWh

ou also need to ask what tires you should run. You’ll only get about 100 different answers

Thank fully I’ve spent most of the day reading up on that… I’ll soon have a stable of MTB tires hanging from a hook I think.

@iamholland

It’s not clear how much you’re going to undertake yourself, but if you’re going to do everything, you’re going to need more bearing press drifts

All of it. I have a bearing press tool. No idea what pivot maintenance looks like! Enlighten me!

@iamholland

You’ll probably need the larger socket, on the fork, at least to open it up. It varies by fork, so see what you need. Make sure to only get 6-point, and flat for shallow, no curved/chamfered edge for the spline or it may slip. There are also spanners for this, but I prefer sockets, as I use my torque wrenches.

Got a link to sockets needed for RockShox SID Ultimate? I have not looked into fork and shock maintenance at all. Only just getting started reading about how to set them up / customize.

@iamholland

MTB tires are not made for that type of pressure. The wider it is, the less pressure it handles. The rims aren’t neither, especially hookless rims.

Got it. So even thought it says 35-60psi on the tire, if I pump it close to max PSI and then treat it like an idiot, it’s likely to damage it? Definitely won’t be doing that again!

@iamholland

You also want a different helmet for MTB. Those roadie lids won’t cut it in a crash. Protect the head at all costs.

Taking recommendations here.

@iamholland

Rent. Period. Packing bikes suck, unless you need it for a race. If for fun, rent.

We live in an RV for the primary purpose of never having to pack bikes
Hated flying with bikes so much that we decided RV life was the way to go. Our RV

@iamholland

Sometimes I rent. It’s lot of wear and tear and accelerated maintenance. Also, if something goes wrong, you can swap it out quick. Not so much with your own bike.

Good to know.

@iamholland

XC Racers tend to be 2.1-2.3. I run 2.5-2.6 myself.

I’ll let my wife play in the 2.2-2.4 range. I’ll stick with 2.35-2.6 if my fork will allow it.

@iamholland

Another thing you will want to learn, suspension setup. There’s much more to it. It’s more of a fiddle and adjust, but you want to know what they do. It depends on the fork and the shock.

SID Ultimate and RockShox Deluxe RLC3 rear. Got links to setting these up specifically? (I’ll google of course!)

To ALL… THANK YOU!

[Dr_Alex_Harrison]

@splash

Forgot to mention, get a stock of brake pads and learn how to change them. In the wrong conditions, you can go through a set in one ride.

Very good to know. Thanks again.

[Rosscopeco]

@Dr_Alex_Harrison

Do I need to remove the thing that the axle goes through to be able to get the tool in??

I believe it should look more like these. Front vs rear.

The through axle at the front requires a different tool that engages with cogs on the outside of the lock ring. (From memory it’s the same tool I use on a shimano BB).
Ignore the DTSwiss branding as I have other wheels with similar Shimano lock rings. They both do the same job.

That pic of yours looks like the previous owner used multigrips to tighten the lock ring.