cheap conversion 8speed hub with 7speed cassette?

[Titiritero]

Hi

I have a rear wheel with an 8 speed cassette (which is badly worn out). I plan to use it in one of my mtbs with 7 speed. I know I would need a 3mm spacer, but I have seen (Sheldon Brown and others) that the spacers in a 8 speed cassette are exactly 3mm.

Is it ok to just remove the bolts holding the 8speed cassette together, take one of the spacers, and use it on the freehub to accommodate my 7speed cassette?

I would hate to pay, no matter how little, for a stupid plastic ring when I can outsource it so easily...

 

[cce]

it's gotta be worth a try if you have the bits at home

 

[legrandefromage]

Yes, but just watch for the chain splicing its way through the spokes to be wedged behind the cassette if you over shift!

 

[integerspin]

More room between spoke and cassette, so less damage, no?

I just checked an 8 speed cassette is 36.36mm wide and a 7 speed is 31.9mm so
4.46mm spacer is needed. There isn't a huge amount of leeway on thickness.

4.5mm that sounds wrong, but I have the cassettes in front of me.

 

[legrandefromage]

You're getting too excited, the cassette may sit proud of the freehub a few nths of a mm but it wont matter - the lock ring will keep it in place.

 

[kingbling]

he's going from 8 to 7 still it should be ok without spacers put on the 7 speed and see what the story is if a spacer is needed add one and just remember to set up the rear mech properly no drama

 

[legrandefromage]

Er, a 7spd cassette is narrower than an 8spd freehub body and will flopsy around if theres no spacer.

 

[kingbling]

there you go add spacer

 

[jgjones095]

I converted my 8 speed cassette into a 7 speed over 10 years ago.
It did involve stripping down the cassette and putting a middle cog at the back of the large cog. Thus increasing the spacing between the last cog and spokes

 

[Silvergoat]

Re:

kind of depends on what speed hub too. A 4.5mm spacer is generally recommended. Also best allowing more space between spokes and 1st cog. Could use a combination of different sized spacers to get fit.