18” rear wheel, longer shocks

[ChasF]

I’m thinking of fitting an 18 inch wm3 rim instead of the 19” wm2.  This would provide a wider choice of tyres but is there a good reason for not ding this?

Any benefits or otherwise in fitting slightly longer rear shocks - I would like to maintain or raise the seat height a little if I can.

[JulianS]

An 18 inch rim will lower gearing and make the speedometer inaccurate.

Longer shocks could foul the pillion footrest securing nuts.

[duTch]

 I'm out of touch with S/A models, but have an 18" on my Plunger but I also have the wrong speedo so the speed is already out of whack, but if you do a 'rolling diameter check on the tyres you want to use, you'll see how they compare, especially when profiles vary a bit, so you may find one that compensates  , but I'm sure you'll hear plenty of ideas

 Re longer shocks; if they do fit as ^^above, you may also need to 're-set' the bushes so they sit in the right place- again  , but that could also start a worm farm

[Tomcat]

An 18 inch rim will lower gearing and make the speedometer inaccurate.

Longer shocks could foul the pillion footrest securing nuts.

I've raised the gearing on my Super Rocket and highly recommend doing the same.  If you go 18" IMHO you will need to raise the gearing x 2.

[ChasF]

One thing that has never worked reliably is the speedo. I’m sure I could get the existing speedo repaired but the cable is a bit of a weakpoint. I’m not keen on too much tech but, given it doesn’t have any influence on the bike’s ability to get me home, I may go for a Speedhut gps unit.

Anyone know if the wm3 rim intended for the A50/65 qd crinkle hub is compatible with the A10 qd hub ( which I think is the same as the Goldstar)

Longer shocks are on the back burner as the Girling units I have are not that old and just need a new chrome/stainless cover.

[duTch]

 

.....Anyone know if the wm3 rim intended for the A50/65 qd crinkle hub is compatible with the A10 qd hub ( which I think is the same as the Goldstar).....

  I have a WM3 x 18" on my A10 Plunger, hub is much the same as the '54/5 S/Arm ones, and A50/65. (neither of the S/Arm ones use the RHS bearing retainer, but same crinkle bit). No point trying to use the Unit sprocket either, unless running a sidecar.

 I bought from CWC, and just needed to specify exactly what you have/need.

[KiwiGF]

I’m thinking of fitting an 18 inch wm3 rim instead of the 19” wm2.  This would provide a wider choice of tyres but is there a good reason for not ding this?

Any benefits or otherwise in fitting slightly longer rear shocks - I would like to maintain or raise the seat height a little if I can.

I’m thinking if you have the wider wm3 rim and fit a wider tyre (say 4”) it will end up being the same diameter as the std wm2 set up? I’ve not fitted wider tyres but hopefully someone can advise if a 4” will fit. If the wheel diameter is the same I don’t think there will be a need to change shocks etc.

Obviously if you fit a low profile tyre this will reduce the diameter compared to a full profile tyre.

[Klaus]

Most of by beesas are fited with a 18" rim and 4.00 Bridgestone BT45 with no Problems. But its very close to the chainguard.
Also no probs with longer chocks, still remember they are 340mm. At my racebike 360mm are used and exelent handling.
My new projekt with Rickman A10 OIF have a an A65 swing arm witch is longer, but the headstock has another angle, so the wheelbase is the same same as original A10. With this longer SA is use 380mm shocks to lift the bike.

cheers Klaus

[ChasF]

Thanks for the comments. I will fit the A65 18” WM3 rim and probably a 4.00 K70

[duTch]

  I'm sure you're aware that whether it's a rim that needs lacing to your hub, or  a complete A65 wheel you need to double- check the offset ?

[ChasF]

  I'm sure your aware that whether it's a rim that needs lacing to your hub, or  a complete A65 wheel you need to double- check the offset ?

I checked the wheel alignment before I dismantled the bike and it was spot on. I will measure the offset on the existing wheel (to the centre of the rim) before I dismantle and then  lace the new rim with the same offset sounds easy but, from previous experience, takes a lot of fiddling about to get the rim true in both directions and with the correct offset

[RichardL]

I've raised the gearing on my Super Rocket and highly recommend doing the same.  If you go 18" IMHO you will need to raise the gearing x 2.

Tomcat,

What do you mean by "x 2" here? That's not right, is it? I was thinking maybe you meant + 2 teeth on the engine sprocket. In any case, I have a higher profile tire on my 18" rear, so gearing and speedo are really about the same as using a 19".

Richard L.

[KiwiGF]

Thanks for the comments. I will fit the A65 18” WM3 rim and probably a 4.00 K70

Shameless plug of my own post on k70 tyre life! https://www.a7a10.net/forum/index.php?topic=11470.msg87150#msg87150

The Duro brand is showing little signs of wear on my a10, after 1200 Miles.

[Tomcat]

I've raised the gearing on my Super Rocket and highly recommend doing the same.  If you go 18" IMHO you will need to raise the gearing x 2.

Tomcat,

What do you mean by "x 2" here? That's not right, is it? I was thinking maybe you meant + 2 teeth on the engine sprocket. In any case, I have a higher profile tire on my 18" rear, so gearing and speedo are really about the same as using a 19".

Richard L.

G'day Richard,
What I meant is by gearing up 1 tooth on the gearbox sprocket I now have a happy engine at 60 mph, still got power but with less vibration 
If an 18" wheel with a smaller rolling diameter is fitted then the gearing will need to be altered to bring down the engine revs.
Cheers TC

[Butch (cb)]

Running 19" front and back on my s/arm and it still feels alarmingly easy to deck the footrests, though I know that these are theoretically adjustable. Will affect the stance on the stands - and potentially harder to get it on the main stand. As you say, suspension adjustments may cover most of this.