76SLT 

I recently picked up an 88 Ironman Master that I want to make some improvements to the gearing. It currently has a 12-21 cassette and I want something more like a 12-28. Apparently these originally came with a 13-24 so it may not be original. The hub is an HF6400 on a Mavic MA40 rim so I know the rim is not original. There's no name on the cassette, just 7s L1 on the smallest gear. This is my first dealings with a cassette, all my bikes use a freewheel. What do I need to look for in deciding on a new cassette?

ramzilla

That cassette doesn't look like anything I've seen before. If it's Shimano compatible this will work:

https://www.jensonusa.com/SRAM-PG-73...QaAgROEALw_wcB

76SLT 

Would the 6400 tri color Rd handle a 32 tooth?

The pic of the back of the cassette doesn't look right so here's a better one.

AeroGut

Looks like you removed the whole free hub? The cassette slides off of that free hub, so you can leave it on the wheel

Bianchigirll 

It appears you removed theUniglide freehub body along with the Uniglide cassette cogs. You need a pair of chain whips to loosen the first cog or two then the rest just slide off.

If it was my bike and the wheel was in good shape I’d find a good used 7spd Hyperglide hub and transfer that axle set and freehub body to the wheel. The 7spd Hyperglide cassettes are easier to source

76SLT 

You're all correct, I removed the whole hub body from the hub. I removed a cassette before but there was a lock ring which this one does not have. Do I need to use two whips to remove the first cog? I only have one. Is there another way?

So this one is a Uniglide?

ramzilla

You can do it with one chain whip if you've got a bench vise. You can just clamp it in the vise & use the chain whip. Or, clamp a sacrificial piece of chain in the vise & around the cassette & use a chain whip.

76SLT 

I'll give it a try, thanks. I've gained a better understanding of what I have and what I need thanks to the help here. I think I'll probably take Bianchigirl's advice and replace the hub.

Bianchigirll 

But just the freehub body and axleset yes? unless the bearing race on the left is worn.



If it was my wheel I'd use something like this to harvest the freehub body and axleset https://www.ebay.com/itm/Shimano-STX...0AAOSw74xdw6cJ

seypat

Is the RD A 62 series or 64 series. If you go to the IM thread, i put some how to guides there about how big of a rear cluster a 62 series RD will shift. I started the how to guides about the time the virus started shutting down. There should be info there to answer all of your questions.

76SLT 

The rd is a 6400. I also have a 6401.

rccardr 

A 640X RD will reliably shift a 28 tooth cog; I would not advise going larger unless using a Wolf Tooth extender.
There are 12 tooth UG first cogs out there but they are rare and relatively expensive.
Agree that installing an HG freehub will make it easier to find the cog sizes you want.

WildWilly

Don't mean to hijack and am having a similar issue. I have a cassette like this with the 7s I got off an 89 Ironman Master that I am trying to remove from a set of ctl-370's. From what I understand the first or second cog is the lock and I need two chain whip tools to unlock and remove?

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76SLT 

You'll need one on the larger cogs to prevent them from spinning when you use the second one to loosen the smallest cog which is the locking cog. I just did it with one chain whip by carefully placing the cassette in a vice. Luckily it wasn't real tight and unscrewed with not a lot of force. Don't know if that's the norm though.

WildWilly

Thank you will give this a try later today. Not sure if this makes sense but your cassette was off the hub already? How did you do that?

76SLT 

The cogs surround the hub body, and held in place with the small cog/lock ring. Once the lock ring is removed, the cogs will lift off the hub body. The hub body can be removed from the hub, like I did, by using a large Alan wrench. Not sure what size. It was largest in my set. Right in the center you'll see where the Alan wrench goes.

A couple days ago I knew nothing about cassettes, but it's really very easy once you've done it.

76SLT 

Here's my new setup. 12-28 Sunrace hyperglide cassette.

WildWilly

Wow looks great Would enjoy hearing an update on how you like the gearing vs the UG. What is your typical daily ride like? Going to have to find that thread from seypat.

76SLT 

I still haven't taken it for a long ride. It's been too hot here. I also have to wrap the handlebars.

You're looking for page 336 of the "post your Centurion Ironman" thread. @seypat did a great job.

ramzilla

Here's my Ironman with a big 12-32 Sram cassette on it. I took the easy route and just put a brand new 130mm wheel set on it with some Microshift brifters and a long cage 105 RD.

This is a Centurion.

RobbieTunes

With a Wolftooth Roadlink, yes.
About $22

76SLT 

That looks great with that wheel set. Nice looking Ironman.

ramzilla

A brand new wheelset solves a lot of drivetrain problems. New rear wheel will always have a freehub preinstalled. All you need to do is decide how many cogs you want + get shifters to match. 7 speed is still my favorite because it's the most economical. . But, 130mm rear spacing fits 8 & 9 speed just as well. It's all good. Have fun.