Using a 7 speed cassete on 9 speed hub?

jimcameron
jimcameron Posts: 199
edited March 2009 in Workshop
Hi,

I've two Giant OCR (2 and 4) and i'm about to upgrade the wheels on the OCR 2 (which has a 9 speed cassette) so i thought i might take the old wheels off the OCR2 and put them on the OCR4. The OCR 4, however, has a 7 speed cassette. Can i just put this cassete straight onto the OCR2 9 speed hub? Or do i need some extras, spacers or something like that?

Cheers

Jim

Comments

  • nicklouse
    nicklouse Posts: 50,675
    shimano? you need a "7spd spacer" 4,5mm wide if i recall.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • jimcameron
    jimcameron Posts: 199
    yeah shimano, does that just fire on the end then or in between cogs?
  • nicklouse
    nicklouse Posts: 50,675
    spacer goes on first and then the cassette as normal.
    http://www.halorims.com/Halo/products-d ... d=CSHAS78C
    csha-cass-spacer.jpg
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • jimcameron
    jimcameron Posts: 199
    Cheers Nick,

    I've just found out a major spanner in the works. Turns out the OCR 4 (7-speed) is a freewheel hub and the OCR2 (9-Speed) is a Cassete hub so i won't be able to transfer across at all. So this begs the question....

    Would i be better for me to just get a 9 speed shifte(and new bit of chain), or to get the 7
    speed cassette and spacer that fits a cassette hub?

    Or would i be fine running my 7-speed gear system on a 9 speed hub? i.e just plonking in the new wheel regardless of the cassette size?

    Thanks for your previous advice, i really appreciate it.
  • nicklouse
    nicklouse Posts: 50,675
    the cheapest option will be a 7spd cassette.

    as you would really need to change most of the drive train other wise to go 9spd.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • jimcameron
    jimcameron Posts: 199
    Sorry i'm back on this again. My sproket ratio is 28T to 14T. If i get a new cassette do i have to match the ratio exactly? Will i have to get a new chain. I'm finding real difficulty finding a 28-14 7 speed cassette for a freehub (hyperglide i think)...
  • nicklouse
    nicklouse Posts: 50,675
    no need to be exactly the same sprocket sizes, and i would be tempted to fit a new chain as a matter of course.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • rickhotrod
    rickhotrod Posts: 181
    A 7-speed 14-28 [14,16,18,20,22,24,28] is a freewheel not a cassette. The Shimano 7-speed 14-28 is often sold cheaply on Ebay. It's probably the most common size freewheel.

    The sprockets are well spaced out with no big jumps except the 24 to 28. Shimano should change the 28 to a 26 or 27!
  • jimcameron
    jimcameron Posts: 199
    Yeah i know. The current hub is a freewheel but the wheels i want to fit have a 9speed freehub on them, so i wanted to find out if i coul get a 28-14 ratio 7 speed cassette. As it works i can get a 30-13 7 speed cassette, as it seems you can't actually get 28-14 cassetes, only freewheels.

    Cheers for the help guys!
  • rickhotrod
    rickhotrod Posts: 181
    Don't get a 7 speed 13-30 (13,15,17,20,23,26,30) cassette. The gears are too widely spaced.

    A 7 speed 13-26 (13,15,17,19,21,23,26) has well spaced gears.

    Slightly wider spaced is the 7 speed 13-28 (13,15,17,19,21,24,28). Although this may be hard to get hold off. I've seen it sold in USA and Germany, but not UK.

    Probably best to change to 9 speed.
  • John.T
    John.T Posts: 3,698
    There are several 7sp cassettes listed here.
    http://www.spacycles.co.uk/products.php?plid=m2b0s150p0