Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

eTap wifi - can I go larger than 32 teeth?

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

eTap wifi - can I go larger than 32 teeth?

Old 01-12-18, 11:38 PM
  #1  
cccorlew
Erect member since 1953
Thread Starter
 
cccorlew's Avatar
 
Join Date: Dec 2006
Location: Antioch, CA (SF Bay Area)
Posts: 6,959

Bikes: Roubaix Expert, Motobecane Ti Century Elite turned commuter, Cannondale F500 Mtn bike, Some old French thing gone fixie

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 91 Post(s)
Likes: 0
Liked 15 Times in 9 Posts
eTap wifi - can I go larger than 32 teeth?

Has anyone stretched the limits of eTaps wifi rear derailer? It's spec'd at a 32 tooth max, but I'd love to go 34 or maybe even 36.
Sinner or winner? Brilliant or ill advised? Catches on fire and burns? No problem?
cccorlew is offline  
Old 01-13-18, 02:40 PM
  #2  
RoadLight
Senior Member
 
RoadLight's Avatar
 
Join Date: Oct 2014
Posts: 195
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 53 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by cccorlew View Post
Has anyone stretched the limits of eTaps wifi rear derailer? It's spec'd at a 32 tooth max, but I'd love to go 34 or maybe even 36.
Sinner or winner? Brilliant or ill advised? Catches on fire and burns? No problem?
Hi cccorlew,

There is no single answer because it depends on your bike's frame and, most importantly, its rear derailleur hanger. Some bike frames and hangers will allow you to use a 36t cog with a short-length rear derailleur cage, let alone a medium-length like the SRAM eTap Wifi. Unless you know someone with the same bike frame and hanger who has already tried to do what you want, then you probably won't know if it's possible until you try it, yourself.

Here are some things to be aware of: First, you'll probably have to unscrew the "B" adjustment screw on the rear derailleur quite far in order to fit a bigger cog. You may even need to unscrew it all the way (or remove it). What you need to do is make sure the largest cog clears the top derailleur pulley by a minimum of 2 mm when shifted to it. If it doesn't, then the chain will lack adequate clearance between them.

Second, letting the B screw so far out will cause the rear derailleur to rotate clockwise toward the rear of the bike. Plus, you'll probably need to use a longer chain. These two factors will combine to create a longer variation in required chain length between the extremes of your gear combinations. The length of the rear derailleur cage may not be able to maintain as much tension at the small end and this can lead to more chain slap and a greater possibility for the chain slipping off.

Lot's of cyclists are able to successfully use a larger-than-rated cog with their rear derailleur and the way you'll know if that includes you and how much bigger you can actually go is probably by trial and error.

Lastly, there are some hanger adapters that effectively lengthen your hanger but they are mostly for Shimano rear derailleurs. Most of these adapters are not recommended for SRAM systems so bear that in mind when you hear about them.

Kind regards, RoadLight
RoadLight is offline  
Old 01-13-18, 03:21 PM
  #3  
TimothyH
- Soli Deo Gloria -
 
Join Date: Aug 2015
Location: Northwest Georgia
Posts: 14,783

Bikes: 2018 Rodriguez Custom Fixed Gear, 2017 Niner RLT 9 RDO, 2015 Bianchi Pista, 2002 Fuji Robaix

Mentioned: 235 Post(s)
Tagged: 0 Thread(s)
Quoted: 6833 Post(s)
Liked 683 Times in 431 Posts
For what it's worth, I'm using a SRAM PG-1170 11-36 cassette with Shimano 6870 GS rear derailleur on a Ninter RLT 9 RDO.

Not sure if it has any bearing on the original question but just putting it out there.


-Tim-
TimothyH is offline  
Old 01-13-18, 07:21 PM
  #4  
springs
Senior Member
 
Join Date: Sep 2008
Location: PA, USA
Posts: 212

Bikes: Emonda SLR, Salsa Warbird carbon

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I use a PG-1170 11-36 with my etap wifli. No problems. 2011 Cervelo RS, stock hanger.
springs is offline  
Old 01-14-18, 12:55 AM
  #5  
cccorlew
Erect member since 1953
Thread Starter
 
cccorlew's Avatar
 
Join Date: Dec 2006
Location: Antioch, CA (SF Bay Area)
Posts: 6,959

Bikes: Roubaix Expert, Motobecane Ti Century Elite turned commuter, Cannondale F500 Mtn bike, Some old French thing gone fixie

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 91 Post(s)
Likes: 0
Liked 15 Times in 9 Posts
Originally Posted by RoadLight View Post
.....Lots of info....see above
Thanks so much for your carefully considered and detailed answer. Info I can use!

Thanks to Springs as well.
cccorlew is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
0ldhippie
Bicycle Mechanics
12
01-31-15 08:22 PM
noob_rider
Bicycle Mechanics
16
10-23-14 10:24 AM
DJDave
Bicycle Mechanics
6
08-11-12 08:50 AM
1/8 kid
Bicycle Mechanics
3
05-29-12 09:34 AM
magohn
Bicycle Mechanics
20
02-25-12 05:04 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.