Question about 8 speed cassette (HG 41)

uart
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Question about 8 speed cassette (HG 41)

Postby uart » Wed Aug 15, 2018 7:12 pm

Hi. I want to buy some cheap 8 speed cassettes, just to disassemble and use as a source of replacement cogs for some of my old retro bikes (mostly 6/7 speed stuff).

I'm not worried about the splines matching (I can mod them in a minute or two with just a file), but I just want to know if the larger cogs on these (32/34T) are "full sized" (as in the same spline as the regular cogs) or if they sit on a carrier.

I know that some of the large MTB clusters (like 11 spd) have the larger few cogs on a carrier, so I just want to check. I really want to use the 32/34T cogs, so need them to be full sized and not on a carrier.

Does anyone know this info. Thanks. :)

Here is the type of cassette I'm looking at: https://www.merlincycles.com/shimano-hg ... 07087.html

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Duck!
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Re: Question about 8 speed cassette (HG 41)

Postby Duck! » Wed Aug 15, 2018 7:38 pm

All the 8-sp. stuff has "whole" sprockets, only the surface treatments & size of the weight-reducing holes differ. All Shimano 7+ sp. stuff except the new 12-sp. XTR uses or is compatible with the same spline pattern (some road 10-sp. uses a deeper spline; these cassettes fit on standard hubs, but other cassettes don't fit on those rare hubs).

6-sp. cassettes are incredibly rare, and as far as I know use the same spline pitch all the way around, not the one wider/narrower ridge/trough found on everything else. Other issues you may find are that the older derailleurs simply don't have the clearance to fit under very large sprockets; depending on vintage, 30 or even 28T may be the maximum they'll work on. Also the shift ramping on the big sprockets may not line up nicely with the next smaller one if it's a bigger jump than that in the donor cassette, so shifting can be a bit rough.
I had a thought, but it got run over as it crossed my mind.

uart
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Joined: Sat Jan 02, 2016 9:15 pm
Location: Newcastle

Re: Question about 8 speed cassette (HG 41)

Postby uart » Wed Aug 15, 2018 9:16 pm

Duck! wrote:All the 8-sp. stuff has "whole" sprockets, only the surface treatments & size of the weight-reducing holes differ.


Thanks Duck. Yep whole sprockets, that's exactly what I need. :)

I've done this before with a closer range 8 speed road cassette and it worked out fine. I just needed to be sure that the wider range MTB ones were the same deal.

Re the splines. Yeah the old 6 speed uniglide ones are different, but you can file out the narrow spline on the newer cogs pretty easily and make them fit. Sure it's a hack job, but I've done it plenty of times to get new cogs onto old retro stuff.

septuagenarian
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Re: Question about 8 speed cassette (HG 41)

Postby septuagenarian » Sat Aug 18, 2018 2:49 pm

I'm in the process of changing an oldish Trek 8 speed jumper to a 9 speed hybrid so I have lots of bits, including a Shimano 11-32T CS-HG30-81 with the back 6 in a cluster and the two littlies freewheeling.

If you think it is worth a tinker shoot me a PM with your address and I'll put in a post bag at no cost to you.

Cheers
Kev

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