Bicycle Mechanics - Simple (?) 6 spd to 8 spd change...

I know this has been asked before - I apologize in advance; I can't find the exact issue I have in the BF archives.

I have an old steel 87' road bike with a 6 spd cassette. I also own a new set of Mavic wheels with Shim 105 hub (8, 9 or 10 spd compatible, I believe).

I'd like to put the new wheels on the old bike, (with a new cluster) - is that do-able? If so, what would that entail?

The rear spacing is 130mm (as measured by me, so maybe it is 128mm?)

I'm not interested changing the frame in any way (I've heard one can make/force the dropouts further apart).

Thanks so much!!

Assuming you put a Shimano Tiagra rear hub, you'd have the 130mm spacing. But, do you mean putting an 8 speed cassette and changing the shifter? If they're friction shifters, I read a 7 speed could be used for an 8 speed setup but I don't know if you could use a 6 speed friction shifter for 8 speeds. Again, from what I read, rear derailleurs don't actually have speeds. However, if you have a 6 speed rear derailleur, I don't know it that would be a stretch to go 8 speeds. So, I'd say you're looking at maybe another right shifter, another rear derailleur. Additionally, if you chose a road rear derailleur, it may only have a range of up to 27T even though some people may use one with a 28T max. cassette. The cable pull is the same for the rear derailleur so you could use either road or mountain shifter for the rear.

even if your rear was 126 you could still jam the 130mm wheel in there without major issues on your old steel frame. So you have a wheel, now you need a casette and shifters. chances are old friction shifters would shift all the way up to 10speeds. lets not forget, the casette hasn't gotten that much wider over the years, they've just jammed more and more gears into the same amount of space. I would recommend looking at Microshift brifters or their flat bar road shifters for an inexpensive set of road shifters if you want to go to 9 or 10 speed but that will probably mean you need a new crank because it may not play nice with 9 or 10 speed chains. IF you go to 8 speed you can look for 2300 or sora shifters that are 8 speed and not have issues with the crank as 8 speed chains are the same as 6 and 7 speed.

I would change anything and everything that needs changing.... I am just wondering if I can "fit" my new wheels (which have Shimano 105 rear hub 8-10 speed compatible) onto the bike frame.

No need to have 9-10 speed cassette - an 8 speed cassette would do. I just wonder if it would "fit", given the bike originally fit only a 6 speed cassette.

Sounds like it would (?) - :thumb:

The wheels were originally intended for another (much newer) bike; I have since sold it in favor of a bike with 26" wheels. Meanwhile, my 87' steel bike fits so well (difficult to find bikes in my size), and I want to fix it up. Didn't want to sell the wheels and get another wheel set, if I can make these work. :D

Thanks for all the input! :)

Your newer wheels should fit your old frame without difficulty.

I would change anything and everything that needs changing.... I am just wondering if I can "fit" my new wheels (which have Shimano 105 rear hub 8-10 speed compatible) onto the bike frame.

No need to have 9-10 speed cassette - an 8 speed cassette would do. I just wonder if it would "fit", given the bike originally fit only a 6 speed cassette.

Sounds like it would (?) - :thumb:


If rear spacing is about 130 mm, the new wheel will fit just fine. If shifters are friction, they'll do 8-speed just fine too.
IME, the derailer/chainrings won't have any issues either. Don't think a 6-speed chain will play nice with a 8-speed cassette, but haven't tried it.

If shifters are indexed, they won't run clean with an 8-speed cassette. Can't figure out how you'd be able to use all 8 sprockets either.

Uh, I read a 6,7 and 8 speed chain is the same width.

ecovelo, it would help if you described the shifters you have.

I would go with an 8 speed cassette though.

Uh, I read a 6,7 and 8 speed chain is the same width.

ecovelo, it would help if you described the shifters you have.

I would go with an 8 speed cassette though.
Not quite. Older 5/6-speed chains are wider than 7/8-speed chains and won't work on them. However, current 7/8-speed chain will work on a 6-speed cassette or freewheel.

just to add to the last line of the post about not wanting to force the dropouts in any way. Be advised that if they are a few mm off you can easily force the wheel in with a gentle push. I believe what you were referencing is "cold setting" the frame by getting it bent to 130mm. Some people prefer to do that so they can not only have the dropout width right but also make sure the dropouts are properly aligned with one another. If someone were modifying a vintage bike to resell as a business it's worth going to this extra detail but for personal use, just stick the wheel in, there are no safety issues with it. Also, if you bike measured out at 128 that could have been because it was made at a time when the technology was changing so the manf put the dropout width in the middle so that either sized wheel could be used just as now some companies make touring and cyclocross frames with 132.5mm dropouts so you can use either road or MTB hubs.

have to buy new shift levers as there are different detent spacings in the levers.

have to buy new shift levers as there are different detent spacings in the levers.

OP hasn't stated what kind of shifters he is using in the first place. if they are or can be set to friction mode he shouldn't have any problems.

Currently have downtube shifters - Shimano 105 SIS. They appear to be in at least "fair" condition. The bike is a Bertoni (likely built by Bianchi) and the model was considered a "sport tourer" - one model up from their low end model.

I measured the dropouts using a fabric tape measure - and I'm not sure how accurate the combination of the measured marks and my eyes, are. I was thinking I read somewhere that many/most bikes from that era had 128mm spacing.

I am just starting out with this bike... learning as I go. Because the ride is so much fun and the frame fits so well, I definitely want to keep it and spruce it up a bit. The Mavic wheel set has been hanging in my study for 2 years! - and I was just hoping I could use them, instead of having to sell them. (I hate selling things!)

motebecane69 - yes, the "cold setting"/forcing the dropouts to a certain width, is what I want to avoid.

This is clearly a "fun" bike - and I have no need to go more than an 8 speed rear cassette; I was just wondering with the rear wheel built with a newer hub - meant for 8,9 or 10 speeds, if the wheel would still fit in the rear spacing of a bike that was built for a 6 speed hub. Sounds like, with all I've just learned from all of you, it should be fine.

Thanks again for all the help! I'm excited to get started.... hopefully the wheels won't hang in my study too much longer!! :rolleyes:

just have fun with it, I started just like you!

There might be a friction mode on your 105 shifters. I think I'd go ahead and try with an 8 speed cassette and see how it goes.

There is a friction setting on those shifters - you just rotate the D ring. Shimano levers work really nice as friction shifters, BTW.

You should be good to go; prolly just need to adjust the limit screws on the RD.

There is a friction setting on those shifters - you just rotate the D ring. Shimano levers work really nice as friction shifters, BTW.

You should be good to go; prolly just need to adjust the limit screws on the RD.

+1

You won't need to cold set your frame for a new road wheel which are currently spaced at 130mm, which is close enough to 128mm (within the limits of a measurement error). You will almost certainly need new shifters IF you want indexing. All the other components except maybe your chain should be fine.

just have fun with it, I started just like you!

Thanks for the encouragement!

There is a friction setting on those shifters - you just rotate the D ring. Shimano levers work really nice as friction shifters, BTW.

I know exactly what you're talking about....

You should be good to go; prolly just need to adjust the limit screws on the RD.

Cool. Thanks!

That's good news about the frame, FastJake... thanks!

put an 8 speed IG Hub in there and simplify your life..

put an 8 speed ig hub in there and simplify your life..

:lol:

Seems that if the OP installs the new wheel with the 105 DT shifters set to friction and makes ure the limit screws are set correctly everything will be golden.

Not that an 8 speed IGH in a road frame is not a nice option... it just isn't as cost effective as using the wheels that are at hand.

Some older friction derailleurs (rear) do have issues with 8 speeds due to a lack of lateral movement but a more modern 105 derailleur should handle 8 speeds without flinching.

I just changed out the set up on my '80's Bianchi. It was 126mm with a 6 speed and I put a new cassette style wheel with 10 speed cassette and it fit fine just needed to flex it out by hand a little.