waldick

I recently got back into cycling after 35+ years. I wanted to make sure I would actually stick with it I bought a cheap used Schwinn Varsity department store bike (the one with the aluminum frame). Anyway the bike has a 7-speed Falcon rear gearset, a low end Shimano SIS index shifter and RD. I was able to get a really nice wheel-set very reasonably. It came with a Shimano 8-speed cassette. I tried to get the RD to work but even though I was able to get the top and bottom gears into adjustment, the gears in between were a disaster. So i tried to limit either the top or the bottom to get to 7-speeds, but again, no joy. From what I have been able to research, it must have to do with a combination of index spacing internal to the shifter and sprocket spacing on the cassette. So what I would like to know is if I buy a 7-speed Shimano HG cassette for the new back wheel, whether it will work with the crappy SIS RD and index shifter.

Before the "get a decent bike" flood starts,... I plan to upgrade next year as soon as I'm sure I'll stick with it...but in the mean time I'd like to use the new rear wheel.

wrk101

Buy a seven speed cassette with a spacer. It should work OK.

TiBikeGuy

Since you have the 8 speed cassette already mounted, why don't you just get the shimano 8 speed shifters. There are ppl selling perfectly working ones when they upgrade to 9 speed or 10 speed ones.

waldick

Thanks for the ultra fast responses.

Upon further review...I just counted the number of sprockets...I feel like a real dumbs**t...its a 10-speed cassette..so if the seller gets me the 8-speed, should that work or work as a 7-speed, or do I still need to change to a 7-speed cassette (or 8 speed shifters)?

SweetLou

If you can get the shifter into friction mode, then it will work. If you can't, then it won't work with the 10 or 8 speed. One problem with the 10 speed cassette is the spacing. The cogs are closer than the 7 speed cogs, so much so that the chain won't fit properly between the cogs and you will have a lousy time. The chain will want to jump all the time. If you want to stay with the 10 speed, then you need to change to a 10 speed chain.
Your options are:
1. Get a 7 speed cassette and use a spacer on the hub body.
2. Get an 8 speed cassette and put the shifter in friction mode or buy an 8 speed index shifter.
3. Keep the 10 speed cassette, put the shifter in friction mode or buy a 10 speed index shifter and get a 10 speed chain.

xenologer

a shimano 7 and shimano 8 speed cassette are close enough in sproket spacing that your 7speed shifter should be able to work with either
-you just have to pick either the largest or smallest cog to be innaccessible if you use an 8spd cassete

most new wheels you encounter will have a freehub spaced to fit an 8spd or greater cassete; meaning a 7spd cassete will need a spacer to take up the extra space.
-a 7spd freehub retrofitted onto modern hub spacing makes a stronger wheel, but this topic is not likely something you'll be pursuing...



simplest solution is to just stick an 8spd cassette on there, it will work fine with your 7spd shifter for now;
someday in the future upgrade the shifter to 8spd to unlock the extra gear
-then again, by then you might more likely upgrade to another bike altogether


p.s. get rid of the 10speed cassette, it will not be useable without multiple expensive part swaps; easily outweighing the cost of the bike itself
...well, a 10speed chain and friction shifter would make it work poorly for about 70$, not a worthwhile purchase, just sell it and use the funds elsewhere

waldick

thanks for all the replies !

I'll stick with "try the cheapest thing first" and install the 8-speed cassette and see how that works. Assuming of course the guy I bought the wheel-set from will swap it out for me, which I suspect he will. He seemed like a good guy. I'll update once I get it all together...the bike that is.

dabac

IME, the 7/8 mix isn't quite as clear cut as xenologer thinks.
Sure, it can be made to work, but getting 7 to run clean on 7 will be easier, both from the start but particularly when stuff begins to wear, get dirty ASO.
If you'd had an 8-speed cassette around, I'd say go for it. But if you still have to get the parts, go for a 7-speed cassette instead.
It will be a somewhat more "user friendly" setup.

dsbrantjr

Another alternative would be to stop throwing money at what is at best a mediocre bike and just ride it with the factory components. An upgraded wheelset will not improve your riding experience noticeably enough that it will make or break cycling for you, nor will 8 speeds be materially different from 7.

You will either find that you like cycling and will want a nicer bike or you don't and will regret having spent time and money upgrading this one, IMO. You are unlikely to get your upgrade money back when you sell it.

waldick

Agreed, but I figured that I'd keep the wheelset as a backup when I upgrade to a new bike and sell the old bike with stock wheels when the time comes.

dsbrantjr

If you decide to put a 7 speed cassette on your 8 speed wheel you will need a spacer behind the cassette. A 4.5mm spacer is used for Shimano-compatible freehubs. You will need a lockring tool to install the cassette and a chain whip to remove the old one. Be sure that the lockring bears on the cassette not the freehub.

Spld cyclist

Maybe I'm missing something here, but can you take the 7-speed cassette off the Schwinn wheel and put it on your nicer wheel (with spacer)? The correct spacer should be readily available at a LBS.

CACycling

I believe the original was a freewheel.

wrk101

+1 The X Mart Schwinns are freewheels.

Seven speed cassettes are readily available at a reasonable price. For instance, Walmart.com has them for $16 with free store pickup.

zukahn1 

+1 may be a better idea to go ahead and upgrade to at speed shifters. Aslo you can buy a mid range 7 speed cassette and a spacer fairly cheap only and they should work with your current setup.

ksisler

Was there something broken on the bike to start with? If not, why not just ride it until you are sure you want to buy another bike?

waldick

There was nothing wrong with the original setup. I just ran across a wheelset at a price too good to pass up. It included several tires as well, which I wanted to use on the trainer. Like I said it was one of those deals that was too good to pass up and I can use them as spare or trainers when I do upgrade.

garage sale GT

The cheapest thing you could do would be to buy a friction shifter. I am not aware of which ones have enough travel to cover eight speeds but I know the old Suntour shifter on my old World Sport handled a modern cassette.

Retro Grouch 

How perfect do you need for it to be? There are actually 2 separate problems: Your shifter doesn't have enough detents for all 8 cogs, and the spacing for 7 and 8-speed cassettes is a "hair" off.

To make it work ideally you'll need to acquire either a 7-speed cassette and install a 4.5mm spacer behind it or acquire an 8-speed shifter. In other words, match either the shifter to the cassette or the cassette to the shifter.

If you'll be satisfied with "OK" shifting try this:
1. Use your derailleur's limit screws to eliminate either your biggest or smallest rear cog.
2 Now shift into the middle useable cog that's left. With both your shifter and rear derailleur in the 4th position, carefully dial the cable tension in or out so that the chain is exactly centered on that middle cog. The spacing won't be perfect, but the slop will be evenly divided between the two directions. It'll work OK and you won't have to buy any new parts.

garage sale GT

He said it clicks into the smallest and largest cogs now, though. So the limit screw will just keep the shifter from clicking into the number one or number seven position. Then he'll have seven speeds and six stops instead of eight speeds and seven stops.

EDIT: OK, this is wrong. The limit screws on the derailleur keep the shifter from going into first gear.

Doohickie

Can the OP take the cassette off his crappy old wheel and put it on the new wheel? (I did that...)

wphamilton

This is what I'd do (or from another online store). This way the old wheel still works as a backup and you stay with the cheaper, longer-lasting chains.

fietsbob

Sounds like you need service at a bike shop more than different parts without service ,
take it into the LBS for a Tune Up.

While you are there you can see the differences the better than X mart bikes offer..
One of them is the service after the sale Box Stores never offer,
on a bike not well assembled, or adjusted, in the 1st place.

bobotech

This is a simple issue. 8 speed cassettes work well enough with 7 speed shifters. The spacing is so close, it allows it to work well enough. The spacing difference is less than the play on the top pulley of the Shimano rear derailleur. But the OP discovered that he had a 10 speed cassette, no way that will work at all.

I would just replace the rear cassette with an 8 speed cassette and use the rear derailleur hi and low screws to lock out the smallest cog. Then when he gets a chance, upgrade to a nicer set of 8 speed non-twist grip shifters down the road.

In a nutshell, 8 speed cassettes work well enough with 7 speed shifters in a pinch since the cog to cog vs shift cable pull amounts are so close, i think 4.8 mm vs 5 mm.

waldick

As soon as I get the 8 speed cassette and get it mounted on the wheel I'll report back...