For discussions about bikes and equipment.
I'm planning to buy a second-hand quality sporty road bike. Most have gearsets geared at 50/34 and 11/25. So the lowest ratio is 34/25 which is a bit high for where I live (lots of hills). Bike would probably have Shimano 105 or Campag Veloce, but maybe Ultegra. (I'd consider a triple, but they are rare)
Can I replace the cassette with say 11/28 or 13/29?? Is there a problem that the chain will be too short? Any other tips?
- Posts: 7
- Joined: Sat Apr 03, 2010 6:13 pm
- Location: Near Tunbridge Wells
I fitted a 13-29 to a Centaur 50/34 set up with no problems.
I also have a 12-28 on an old Ultegra double.
Both set ups work fine but check the chain length as you may have to add links.
A rabbit only eats vegetables, hops all day and only lives for 5 years.
A tortoise doesn’t run, does nothing energetic and lives for 450 years.
And you tell me to exercise. ??
- Posts: 3774
- Joined: Sat Jan 17, 2009 9:30 pm
- Location: Lancashire
the largest sprocket you can fit varies with the rear mech model. The manufacturer's specification will either mention the hanger length or assume that it is short. In addition they seem to be a little conservative anyway.
The net result of this is that you can usually go 1T larger and sometimes 2 or 3T larger than the spec (on a slightly longer hanger, say). Each 2mm of hanger length (or 'B' screw adjustment) is 'worth' an extra tooth on the largest sprocket size.
A 'safe' chain length is usually to fit the chain so that it is the correct length to run round the large-large gear combination plus two links.
If you exceed the total mech capacity then the chain may run slack in the small-small combinations. This is often OK if you know about it; those gears may well be duplicated on the big ring anyway, so you don't necessarily need to use them.
- Posts: 19660
- Joined: Wed Jan 04, 2012 6:25 pm
Personally, I'd go with the 34 to 25.
Ride up some hills and wait for my legs to get stronger.
I'd spend the £25 that the cassette would have cost on some nice fillet steak and preserved my bragging rights.
- Posts: 4192
- Joined: Sat Jan 30, 2010 9:54 am
Hi i have just had the Gears fitted to my Raleigh Banana bike because it was too difficult to peddle ,i am new to Road cycling so i am not sure what i have but it is a dream ride,Brian.
- Posts: 2
- Joined: Sat Sep 22, 2012 6:23 pm
Return to Bikes & Bits – Technical section
Who is online
Users browsing this forum: 531colin, Brucey, georgew, Google [Bot], Samuel D, Yahoo [Bot] and 10 guests