So very, very, very confused...again.

Hello

I have tried on another site but...

I have in my possession;

1. Regina Corsa Cassette 15/17/20/24/28

2. SR Royal Cranks/Chain Wheels 53/42

3. Six speed Sun tour Power.... downshifter...don't know why 6?...should it be 10?

Therefore: 10 speed(?)

Therefore: Drive chain capacity = 25(?)

Q. So what kind of rear derailleur do I require?

Q. Can I assume a short cage?

Q. A vintage rear derailleur or can I buy a new one?

Q. Friction or non friction

Thank you

Comments

  • Wheelspinner
    Wheelspinner Posts: 6,712
    I'm not sure you'll find "non-friction" shifters for a 5 speed setup. Your cassette is 5 speed, so the shifter theoretically should match (and be 5 speed), but if that Suntour unit is really just friction rather than index (click stops for each gear) you may be ok. Don't know whether it's called "6 speed" just to indicate it has enough range of movement to cover that.

    You will need a rear derailleur that matches the shifter (broadly speaking). The derailleur movement is matched to the cable pull the shifter does, and they need to be compatible. Assuming it's friction shift, if the shifter is not a "match", you'll get either not enough shifter range to cover all the gears (because the derailleur doesn't move far enough for each cable pull per shift) OR the lever position will be way too sensitive to be useful if the other way round..

    Short cage *might* be fine, but remember that back when that gearing was the norm that a lot of race "cassettes" were crazy like 12-21 or similar, so a 15-28 is relatively wide range for the period. Finding a rear derailleur that's in working condition for that era to suit may not be easy... A top gear of 15 is pretty short. Would have been for a touring bike rather than race I expect, especially with a 28 bottom, so look for a rear derailleur more aimed at a touring bike than racer.

    Lastly, does your wheel set and frame accommodate this? The spacing between the rear dropouts required for a wheel with a 5 speed block was typically 120 or 126 mm I think, while anything from 8 speed onwards was 130 (and now most are 135 or 142 with disc brake stuff). Your wheel free hub will need specific tools too I'd guess.
    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • Hello.

    Thank you for taking the time and effort to reply.

    I have decided to go back to the idea of a single speed free wheel.

    It's all proving to much of a headache.

    So can I ask 14t 16t or 18t, I can't by all three to try them out and then decide due to cost.

    Also can I just use the 42t chain ring and not remove the 53t one or do I have to remove it?

    Then what chain size would be applicable for my RRA circa 1984?

    Sorry...

    Yep I know lol

    Thank you
  • Wheelspinner
    Wheelspinner Posts: 6,712
    If you just use the 42, no need to remove the 53, because if you do, you will need shorter chainring bolts to keep the 42 in place. Which is not a big deal, but has to be done.

    With a 42 front, I'd use the 16 or 14 at the back, unless you live in a really hilly area. Probably the 16 would be my pref for all round use. My last single speed roadie was 46 * 15 and it was great on dead flat terrain, but any hills at all quickly got to be hard work.

    Does your frame have the horizontal dropouts with the tension adjuster screws? Easy to do single speed if you do. Modern vertical dropout frames are much harder to convert to SS and get lucky with chain tension.

    The chain size is still pretty much the same pitch (link length) it's always been. The difference is that the more gears you have, the thinner the chains are (side plates and pin roller bits) to fit in the narrower gap between cogs. You can buy a 5 or 6 speed "size" chain pretty cheap.
    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • Hello

    Thank you for the handy and easy to understand info.

    Great! I didn't really want to remove it...

    There are a few mild hills so It would prob be 18t...I will see how it goes.

    Yes the Raleigh Record Ace circa 1984 does have horizontal drop outs and lucky enough with the screws still in place as often I believe they are missing.

    You have been very helpful. Thank you again and all the best!
  • figus1979
    figus1979 Posts: 22
    edited August 2021
    Hello

    "Yes the Raleigh Record Ace circa 1984 does have horizontal drop outs and lucky enough with the screws still in place as often I believe they are missing."

    Just had a thought, they are not horizontal as like a track bicycle frame but they are suntour drop outs which are/look horizontal to me and do have two screws which may help to keep the rear wheel centered(?).

    I have seen a couple of RRA on the web using a single speed set up...

    Thank you
  • Wheelspinner
    Wheelspinner Posts: 6,712
    figus1979 said:

    Hello

    "Yes the Raleigh Record Ace circa 1984 does have horizontal drop outs and lucky enough with the screws still in place as often I believe they are missing."

    Just had a thought, they are not horizontal as like a track bicycle frame but they are suntour drop outs which are/look horizontal to me and do have two screws which may help to keep the rear wheel centered(?).

    I have seen a couple of RRA on the web using a single speed set up...

    Thank you

    Welcome, and yes you should be fine with those dropouts (usually). One tip will be to ensure you use a good QR skewer, the “internal cam” type like most Shimano ones, and check that the hub lock nuts which sit against the inner face of the dropout are clean and preferably still with that bit of serration, not worn smooth. You’ll also need to ensure the QR is done up probably tighter than you think is normal to keep the wheel from slipping forward, but done right it’s generally fine. Unless you are a track sprint monster.

    If all else fails there you can get things like a Surly Tugnut which will really sort it, but for most, if the QR is tight enough you’ll be ok.

    Final: you can get a “half link” style chain that fits standard pitch road chainrings and sprockets (not track racing or BMX ones). Those give you finer control over the chain tension because the links are shorter. I’ve not tried one and opinions vary on the durability, but KMC generally do decent stuff.

    https://www.kmcchain.com/en/series/half-link-series

    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • Thank you Wheel Spinner.

    Will check out the KMC website via link.

    Ordered a Shimano SS FW this afternoon and feel a lot more confident about the whole thing.

    Will look at gears some time in the future after learning the basics...hopefully.

    Take care

    Pp