That’s really weird gearing. What does he need a 56-teeth front chain ring for?!? Professional time trialists run that kind of gearing, although they do that for efficiency, not because they need a 56:11 top gear.
And at the same time the same person needs a 34:42 low gear?!? That doesn’t make any sense to me.
Well, whatever floats your boat.
I think it might be so he can pedal during longer fast descents when the speeds go over 35. So he doesn’t spend 50% of his endurance rides coasting downhill.
Is that really necessary? A 50:11 at 100 rpm would do the job.
Where I live there are few safe descents where I can safely let it rip beyond that speed, and I rarely if ever spin out. I tried a 52:11, too, and I can think of two, three descents where I can make use of the extra gearing. Plus, at speeds beyond 60 km/h I’ll typically let gravity do the hard work for me.
It’s probably not necessary but I know he generally likes to pedal closer to ~85rpm so the bigger chainring would help him stay in that range. Also, where he lives there are a decent number of fairly straight descents that average 4-6% so you could safely pedal at 40+ mph.
Wasting energy at that point…anytime I hit 35+mph on a descent, I just coast and tuck. Having done IMMOO twice, I always passed other riders who were pedaling on the descent.
He has his training bike set up like that. I don’t think he’s got that wild gearing on his race bike. So it’s not about going as fast as he can but so that he doesn’t spend 5-10 min of each hour coasting downhill because he ran out of gears.
I just pointed it out initially to say that you can get away with some pretty wild gearing if you want to and you are a bit clever with it. Not that it is the best or most practical thing to do.
I do not have a Venge, but I have run 52/36 and 11-32 on Dura-Ace Di2 9100 (hydraulic version). It shifted fine. As others have said in this thread, Shimano is a bit conservative in their maximum gearing specifications. It worked fine, though I’m not sure I would run it daily unless I lived in the mountains, just to make sure I wasn’t putting unnecessary strain on the RD.
Late reply, but… Do you have to change your chain when you swap cassettes? I’m looking at picking up a 52/36 with a 11-28 cassette bike (medium cage Ultegra), but want to swap the cassette for an 11-32 or 11-34. Hoping to not have to change the chain (almost certain with the 34).
@iamholland Thanks. Sorry for the confusion, but I was replying to @bolton who said he had this setup (52/36 with 11-28 and 11-32 cassettes) and said he switches them. I was wondering if he got away with using the same chain when switching and if so, how long it is.
No, I don’t change the chain. It’s cut for 11-32 cassette and I use it with 11-28 daily basis.
thanks.
Yup, I do too with my trainer (11-28) , 28s (11-32), and 40s (11-32) but my current bike’s big ring is only a 46 - not a 52. Bolton happened to describe the exact ratio scenario I was looking at. Thanks for your help.
Swapping the cassette is pretty easy if you have the range on your rear derailleur. 52 in the front and a 32 in the back will get you up most things.
I have found this site useful on the question of changing chain length for different gear sizes. Look up the geo chart of your bike in mm, select the correct options in the drop-downs, and I have found it to be accurate.
http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html
Hi I have also got a similar question to the one here…
I have a RD 6800 SS with 52/36 and 11/25. I’m going to be in Tenerife next winter/spring for a family member’s brithday and was considering training and bringing my bike to do Mount Teide.
However, I’m a bit concerned that this ratio will make that climb really hard, even though the gradients apparently don’t event get too steep.
I don’t have a ton of $ to replace the whole groupset so curious to hear what people think about doing long climbs with this ratio.
Just throw on a 28t cassette if you have a short cage or a 32t if you have a long cage. Just need a lock ring tool and 10 minutes.
You haven’t climbed Mt Taide but I did a lot of climbs on Alps. This ratio is not optimal for me. 25 is not enough but you dont have to spend tons of $ to change the cassete (11-30 or 11-32) and rear derailleur.
Look into a wolf tooth road link. I used 2 on 2 bikes to get 11-32t where without I would have been limited to 11-28t.
I have 52 36 upfront but found a used set of 50 34 to try as well but haven’t installed yet.
You may not even need to change chain length.
6800ss is officially rated to 28t, but Shimano specs are pretty conservative, and you should be able to get a 30t cassette on there without needing a new derailleur. You may need a new chain, but chains are consumables - you will probably need a new one by next winter anyway.
I had 11-32 on sram red short cage and now on dura ace short cage. Front is 36/52 and it works