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Upgrading Crank and Chain Rings(6 posts)

Upgrading Crank and Chain RingsLee M
Mar 12, 2001 7:12 PM
I want to upgrade my road bike gradually. Can I upgrade the old 105 double crank to a new Ultegra triple and still keep the 7-speed cassette? I'm wondering about problems with making 7-spd a chain work on the new narrower chainrings. Should I use a 7-spd chain or one of the new 9-spd chains? What other problems would I run into?
I wouldn't do it.Spoke Wrench
Mar 13, 2001 6:16 AM
I've done a lot of upgrades, but I've never done that particular one. I suspect that it might work, but sometimes subtle differences in spacing between between parts will cause shifting difficulties. You can almost never change just one part on a bike. I'd be cautious of advice given by anyone who hasn't made this EXACT upgrade.

Mixing and matching 7/8 and 9 speed components may result in OK performance or it may degrade performance. It will never improve performance. What you are talking about is some combination of 9 speed chainrings and 7/8 or 9 speed chain, front derailleur and shifters. STI triples can be a pain to adjust when all of the parts match. This looks to me like a receipt for unacceptable front shifting with no idea which additional parts will have to be replaced to make the shifting adequate.

Finally we come to the cost factor. Buying one component at a time is the most expensive way of doing it. The least expensive way to buy bicycle components is to buy a whole bicycle that has the parts that you want. The next best way is to buy the whole component group at one time. We're talking BIG savings.

My advice:

I'd use this bike as an opportunity to fine tune my position first. I don't know how much experience you have, and I don't want to insult you, but I've seen altogether too many people who want to make expensive upgrades on a bike that doesn't fit them. If you are POSITIVE you have the right frame size, experiment with stem length, bar height and saddle position until the bike just "feels" right. This kind of tinkering has the added advantages of both boosting your performance and being relatively economical. I think that this is the knowledge that defines who the real bike people are. If you read the posts on this bulletin board for a while, I think that you will agree with me.

Once you are sure of the fit issues, you can make the decision to upgrade this bike or to buy a new bike. You'll be a lot smarter because you will be sure of all of the sizes you need. If you decide to upgrade, do it all at once.
Bitter experience says Spoke Wrench is rightRetro
Mar 13, 2001 7:46 AM
FWIW, I agree--you could probably make it work (my commute bike is a mishmash of unrelated salvaged parts). But there's so much stuff out there that isn't quite compatible that it's more trouble and money than it's worth.
Make sure the frame's what you want; meanwhile save your money and wait for a sale somewhere, then get everything you need in one swoop.
I wouldn't do it.Lee M
Mar 13, 2001 10:25 AM
Thanks for taking the time to give a lengthy and well thoughout reply. The bike was custom built of Reynolds 531 in 1993 so I'm not too anxious to replace the whole thing. Plus I have two kids under 4 so spare Scheckles are a little rare. That's why I wanted to do it gradually. Sounds like I should upgrade to 9 spd at the same time as I do the BB and crank.
I do it all the time......Mongrel Biker
Mar 13, 2001 1:09 PM
...but it is a task better left to the well informed do it yourselfer who isn't afraid to think out of the box, has lots of parts lying around and knows how to tinker and and adjust till it all works. Every bike I got is a mix and match mongrel,but it all works perfectly. Basic rule on this is "if you have to ask,you probably shouldnt be doing it".
I do it all the time......scooter too
Mar 20, 2001 9:02 AM
I have a similar question about putting a road cassette on my commuter bike. I'm running old (1990) top-mount mountain bike XT 7-speed shifters, an old (1993) 7-speed cassette, an new IG-90 chain (8-speed), and an STX-RC (1997) rear derailleur. Because I can run the shifters in non-SIS mode, I believe I can run an 11-22 8-speed cassette, back the derailleur stop screws right out, and basically manually shift the rear derailleur. That's basically how the front shifter works anyways as it does not index. Feasible?