Hello everyone,

A few months back I purchased a 1988 Schwinn Tempo, and completely overhauled it, including new pads, cables, cable housings bb, brake levers, etc.

There is an incredible place to ride up here called Going to the Sun Road, and while scenic, is also a very long mountain climb. I can barely make it to the top, but my cadence is probably about 20 rpm in the lowest gear since the smaller front chainring is 42T and the largest in the rear is 24T.

The groupset is all Shimano 105, with indexed downtube shifters, and a 6 speed freewheel.

I know I should probably just get in better shape, but is there an easily available freewheel that I can swap for the current one so I can at least improve cadence a bit? If I purchased a 7 speed with the largest being a 28T would that work with my existing 105 rear derailleur? Would that throw off the indexed shifting? I know 600 tri-color stuff from the same era was designed for 7 speed.

I also want the best breaks possible for the descent - would something like an Ultegra br-6500 be a direct swap for the center pivot 105s that are on there now?

Thank you for any help, I know just enough to be dangerous. If any of you ever get the chance, the ride Going to the Sun.

Well I know you’re not in my neck of the woods! Where are you for that kind of scenery greatness?

Merckx” Don’t upgrade, ride up grades!”

A 7-Speed would have narrower spacing and would not index with a 6-Speed shifter.

You should be able to find a used or NOS vintage 6-Speed that has bigger than 24.

Shimano and Sunrace still make new freewheels but I can’t recommend the Shimano. I don’t think the modern ones are as well made as older Sachs, Suntour, Regina and so on. I had one start to misbehave after at most 1000 miles.

IRD is making new free wheels in 5,6 and 7 speed versions. They cost a good bit more, but seem to be better made. And they supply replacement parts. They have 6 speed models that go up to 24, 26, 28 and 32. The jump on the 32 is from 24 which is a lot.

Anyway, here is the link:

https://www.interlocracing.com/shop/...arch=freewheel

Hope that helps.

Otto

eBay is full of 1980's low mileage 13-28 and 14-28 UG 6 speed freewheels that last forever, will fit on your bike, and interface with your indexing system.
Prefer new or like new? Check PastorbobinNH or his website the Freewheel Spa. He'll make one for you at a reasonable price.
You will likely need a new chain or at least a few additional links if yours is new, but everything else will work together just fine.
Note to self: ALWAYS keep any extra links from a new chain that is shortened to fit.
6500 double pivot brake are an upgrade, if you can get them cheap. do it. Everything else won your bike will work with them.

This page suggests you should be able to get to a 28-tooth large cog, and the 26-tooth chain wrap should accommodate the 52-42 rings with 14-28 freewheel: VeloBase.com - Component: Shimano RD-1050, 105

I've had good luck with Sunrace, and they make a 6sp 14-28: https://www.amazon.com/SunRace-Speed.../dp/B07C1533KF

As noted above, you'll need a longer chain.

rccardr nailed it.

I can only offer high praise for the 6500 brakes. They are fantastic. Make sure you run them with good pads - R55C4 I think is what I have. Excellent performance.

Are we certain that the hub is freewheel and not cassette? Check into that before committing to a new-to-you freewheel.

You can also purchase a 39 tooth front chainring with correct BHC pattern. I think 130mm, but unable to verify at the moment. 38T were made but more difficult to find.

Did anyone make 6 speed cassettes? I don’t know, I’ve simply never heard of anything less than 7 speed in a cassette.

Otto

Yep, Shimano Uniglide

Did that use the same freehub they used for 7-speed or a separate model?

Otto

My ‘79 Miyata 912 originally came with a 6-speed Uniglide cassette. It would be too short for a 7-speed. That first use of free hubs/cassette did not yet have replaceable freehub bodies.

OP isn't kidding. Wow.

You did a great job on the Tempo. Personally, I wouldn’t be too anxious to start mixing up the components on it. Maybe a full trade up to tri color or Dura Ace 7400 if anything.

Until then, 28 teeth on the back will make a big difference. I’ll assume the cranks are 130 BCD in which case I’d also put a 39 on the front. Doing both might get you by without changing chain links. 39/28 will be the limit with a short cage derailleur and standard crank BCD.

Thank you all very much! Based on your advice I'll either track down a 39 tooth front chain ring or a 6 speed freewheel with a 28 tooth large cog to start with.

If I did want to "upgrade" to the 7-speed setups of that era at some point, would my current 105 derailleur be able to handle it, or would I need a new rear derailleur, shifters, and freewheel?

If I'm remembering correctly, I think the current rear freewheel is a Uniglide. Should I be looking for a 28T hyperglide freewheel to improve shifting performance? Were these even made, or are they all cassettes?

In addition to the suggestions already made, you may want to try some clipless pedals and cycling shoes. They can be very helpful for climbing.

That looks like a truly awesome ride.

If you look closely in the first pic, the bike actually does have those cages and straps over the pedals - I had to take them off as my foot is too long since it hits the end of the cage before the ball of my foot is over the center of the pedal. They were removed for the subsequent rides - I've ridden this road 3 times in the last week and a half, and that pic is from the first time. I really should get a pair of clipless pedals and correct shoes.

Would you remove the rear wheel and take a closeup image of the cogset from the side? That way we can tell you if it's a freehub cassette or a freewheel.

Cheers

I just used Sheldon Brown's gear Calculator to show you the differences you'd get with a 39 teeth chainring and/or a 28 teeth rear cog.


Cheers

Toe clips come in sizes. You might need a L or XL.

Toe-clips can be moved out from the pedal a bit if you use longer bolts and spacers between the toe-clip and the pedal.

Cheers

If your hub takes a freewheel this will work fine with Shimano 6sp indexing.
If you have a cassette, it's an easy matter to change out a few sprockets. In that case, I would grab this cassette and adapt some of the larger sprockets to your freehub. No rocket science needed.

Your Shimano 105 rear derailleur possesses the standard (well, since they came out with it back then until only recently) 1.7:1 cable pull ratio. Basically, outside of 7400-era Dura-Ace, 10-speed Tiagra (4700), and all the 11-speed stuff, any Shimano SIS road rear derailleur will work with your shifters to shift those 6 gears out back. There are about eleventy-billion of them to choose from, thankfully. Any Shimano road RD of those choices will handle a 28T no problem, even if Shimano shorts their capability by 2 teeth.

Kudos for you getting up that climb. Looks like you have Biopace chain rings. Do you like them? If not, getting some normal round ones can help, though Shimano designed that 42T inner ring to behave like a smaller chain ring and out of the saddle in grind mode, the Biopace stuff worked well for me. For anything normal, roundy-round rings are the only way for me.

Do you have an approximate budget in mind for these several upgrades? That drives a lot of things. 6500 brakes are very nice, but I personally would bump to the next generation of Shimano road stuff (105 - 5600, Ultegra - 6600, Dura-Ace - 7800) as the geometry got better, dealing with wider rims and tires more easily, and being stronger overall. Most anything in the dual pivot architecture will be an upgrade over what you have now (single pivots), and getting good Kool Stop pads will help noticeably. So if you're set on 6500s, then go for them.

If he has a UNIGLIDE cassette he'll need to grind off part of the large tab on each cog from that Hyperglide cassette in order to fit the cog to the Uniglide freehub body.

This is why I asked the OP to post an image of his rear wheel that shows the cogs from the drive side. Then we'll know what he's dealing with, cassette or freewheel.

Cheers

I.e., not "rocket science". Or, do you disagree?

Not rocket science nor do I disagree. However the OP may not have been aware of the need to grind down the large Hyperglide cog tab in order to fit it to a Uniglide cassette body. Heck we don't even know yet whether or not the OP has a cassette or a freewheel.

Cheers