Bicycle Mechanics - Moving from 7 speed cassette upwards gear-wise

Okay, noob mechanic here.

I've just bought an older bike with a 7-speed cassette on the rear hub, a Shimano 105, HB1055. The frame's dropout spacing is less than 130mm - probably 126 or so (my eyes/ruler are telling me 126mm one measurement, 128mm when I doublecheck).

Does that allow enough space to upgrade to an 8 or 9 speed cassette? I thik I read somewhere that 8, 9 and 10-speed cassettes all take up the same amount of space, just the width of the individual cogs changes.

And, can anyone refer me to a source on how to replace the cassette itself? I find myself 'Net-search function challenged this morning.

Thanks.

An 8/9/10-speed freehub body and the corresponding cassettes are wider than a 7-speed body so an 8-speed or up cassette won't fit on it. You can swap an 8+-speed freehub body to a 7-speed hub but that will get you a 130 mm OLD hub in the proces. It is possible to run an 8-speed freehub body at a 126 mm OLD but the required wheel dish (or offset if you prefer) will be excessive.

Depending on your frame, it is possible, and some times easy, to force fit a 130 mm hub into 126 mm dropouts or if the frame is steel, have the dropouts "cold set" to 130 mm. In fact, if your frame is really 128 mm, it was built during the change period when both 7 and 8-speed bikes were built on the same frame at different price points. My '92 Trek 1420 was made just that way.

Did you mean FH-1055? The HB-1055 shows as the front hub here http://www.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50rparsys-0034-downloadFile.html/07)%20Hub%20Specs.pdf

A 7sp HG freehub cannot fit an 8, 9, or 10sp cassette. 7sp cassettes are ~31mm wide and 8/9/10 are ~35mm wide. You can fit 8 cogs of a 9sp cassette, or 9 cogs of a 10sp casssette, though. You could transplant a 8/9/10sp freehub onto your hub but you would then also need to redish the wheel. Any change to 8/9/10 would require changing shifters unless you have friction mode and switch to that.

To remove the cassette, use a Shimano HG compatible cassette lock-ring tool, a wrench, and a chain whip.

More "speeds" ? what Ratio are you seeking, for what riding condition/situation you encounter regularly
that you do not have available with the cassettes and/or freewheels that fit already?

doing a frame spread + new wheel + cassette +chain+indexed shifter perhaps shop labor to do the work,
gets you up to an N+1 resolution, in cost , of just buying a new Bike.

Frame spread/cold setting is not a viable option. It's an aluminum frame.

Frame spread/cold setting is not a viable option. It's an aluminum frame.

Coldsetting is not, but spreading the stays is. Many people spread the stays to fit 130 wheels very often. I've done it multiple times and the bikes are still holding strong. It is only ~2mm on each side. BBs on aluminum frames flex more than that during general riding.

Some bikes were built with intermediate rear spacing too.

No problemo.

More "speeds" ? what Ratio are you seeking, for what riding condition/situation you encounter regularly that you do not have available with the cassettes and/or freewheels that fit already?Reasonable question. While many people used to ride 5 seeds and think that was all that were ever needed, having more gears available, though there will likely be a fair bit of overlap, makes things easier at times, period. I happen to have a couple of 8 speed wheels, spare tires and tubes lying around and am trying to maximize my use of what I already have and like. The 7 speed setup has overlap and gaps with its triple crankset that is different and less desirable than my 8 speed setups on other bikes/trikes.

I figured it might be "easy/easier" to change the rear cassette, but now, it's obvious that changing the middle ring on the crank is probably the way to go. DOH! Thanks for asking the question in a way that got me to thinking about what I actually wanted to accomplish.

Thanks to everyone who replied.

And, can anyone refer me to a source on how to replace the cassette itself? I find myself 'Net-search function challenged this morning.


I don't know if your still looking for a source of cassette replacement. I really love Zinn and The Art of Road Bike Maintenance. http://www.amazon.com/Zinn-Art-Road-Bike-Maintenance/dp/1934030422/ref=sr_1_2?ie=UTF8&qid=1322878979&sr=8-2It has a good section of cassette and cassette replacement, anlong with everything else you need to know. I'm somewhat of a noob mechanic myself and i learned a lot from it.

Anyway, I don't mean for this to sound like a sales pitch, but i think it is a good resource.
Hope it helps, good luck to ya.

ksharp117 - thanks for the reference. I'll look into getting a copy.

Many of the later generation 7-speed bikes had 130 mm rear dropout spacing. And many 7-speed freehubs could be upgraded with 8+speed freehubs without having to rebuild the rear wheel, although it would probably require re-dishing.

dreamweaver2, It's really no big deal for a 126 mm OLD aluminum frame to accept a 130 mm OLD hub, my '89 Cannondale has been 'converted' since the mid '90s without issue. If you replace the 7S freehub with an 8S freehub the wheel will require redishing, however.

I like 8Ss and I have extra cassettes to swap around to fine tune a bike to a particular route. If the bike is most likely to be rode along a more or less dedicated route, the chainring swap makes sense.

Brad

lots of mies on bike tours , 7 speed freewheels , 13~32, triple 24,40,50t. 126 frame
ratio spread was adequate, ultimate low as always ... get off and push.

last frame, custom, is substantial, steel loop stays,
wont bend, 3/4 .049 wall chromoly, easily, to change.

for 135 rather than spread, I got another Bike..

dreamweaver2, It's really no big deal for a 126 mm OLD aluminum frame to accept a 130 mm OLD hub, my '89 Cannondale has been 'converted' since the mid '90s without issue. If you replace the 7S freehub with an 8S freehub the wheel will require redishing, however.

I like 8Ss and I have extra cassettes to swap around to fine tune a bike to a particular route. If the bike is most likely to be rode along a more or less dedicated route, the chainring swap makes sense.

Brad

I like the idea of upgrading my 7S to 8 or 9. Is it correct that I could fit 8 cogs from a 9S cassette, or 9 cogs from a 10S cassette on my 7S hub? If so, would re-dishing be unnecessary, but a new indexed shifter (8S or 9S) be required? Also new chain? If so do you know a good source for used parts?