lacing an 18 inch rim onto the 17 inch gs hub

jackassdave · Mar 16, 2023

im sure its been done saw a very brief thing on adventure rider , there's plenty of 18 inch rims around and fairly cheap compared to std gs rim / wheel etc .
how easy would it be to do , is there offset ? , does 1 inch on the size alter the bike that much ? , certainly a lot more tyre choice

Mad Hatter · Mar 16, 2023

jackassdave said:
im sure its been done saw a very brief thing on adventure rider , there's plenty of 18 inch rims around and fairly cheap compared to std gs rim / wheel etc .
how easy would it be to do , is there offset ? , does 1 inch on the size alter the bike that much ? , certainly a lot more tyre choice

Like this?

Mad Hatter · Mar 16, 2023

18” conventional rim laced to 4 bolt gs paralever hub needs no additional offset and there’s just about enough clearance for an 18 x 4.00 tyre

AnotherGSGSGS · Mar 17, 2023

Do you mean the common 36 spoke rims found on most enduro bikes that are not compatible with a BMW 40 spoke hub? Harley use 40 spokes I think and possibly some English bikes. On Mad Hatters wheel the spoke angle will have changed there. It's either bending spokes or re-drilling the nipple hole to the correct angle or some other jiggery pokery. It's a double threaded spoke too to fit 2x nipples.

I'm weighing up whether to do this same mod as I have an 18" rim that came off a mono hub.

jackassdave · Mar 17, 2023

Mad Hatter said:
Like this?

.

no onto a 1150 rim so it takes tubeless tyres

MickDB1 · Mar 17, 2023

You can still make just about any spoked wheel airtight with the right conversion kit.

Mad Hatter · Mar 17, 2023

jackassdave said:
.

no onto a 1150 rim so it takes tubeless tyres

Other folks have done this using a tubeless 18” front rim off a R100R laced to a gs four bolt hub

jackassdave · Mar 17, 2023

Mad Hatter said:
Other folks have done this using a tubeless 18” front rim off a R100R laced to a gs four bolt hub

ahh that's interesting I may look out for a rim ....top man

AnotherGSGSGS · Mar 17, 2023

jackassdave said:
.

no onto a 1150 rim so it takes tubeless tyres

I've built 3 custom wheels lacing various tubeless rims onto my LC GSA's hubs. Contrary to popular misconception BMW x-lace wheels are easy to build. The rear I've just built took about 1hr to lace up and get true enough. The hard part with rear wheels is how to hold the hub true so you can spin it. I used my lathe chuck to hold the hub which was fitted onto a wheel stand. The run out gauge is then used to check the measurements.
You also need a 5ftlb torque wrench. Using trigonometry you calculate the spoke length needed, get central wheels in Birmingham to make you some custom spokes. The art of the quick build is to get it right before you lighten everything up as you cannot true the tubeless rim in the conventional sense merely make congruent with the hub in 3 dimensions. You then have to work in opposites and make very small adjustments and keep checking. Not hard, you just need to concentrate. The first wheel I built took me most of a weekend to true up as I had to make a kind of jig. The worst part is stripping the tubeless wheels and getting the seized in spokes out.

Mad Hatter · Mar 17, 2023

Can you explain more about how you calculated the spoke lengths please?

AnotherGSGSGS · Mar 18, 2023

Sure,

I use this method as you can calculate the spoke deflection as if you change the rim size the hub holes and rim holes will no longer align unless you make some kind of alteration.

When I laced the 21" airhead rim onto the LC hub that was quite a big change in spoke angle which isn't great really having radiused spokes.

Hopefully these should explain
"Howie did it" for the Binky fans.

wheel2-1

wheel2-2

wheel2-3

These are only approximate dims quickly measured this morning. The autocad dimensions are measured lengths and angles not manual inputs.

tuftywhite · Mar 18, 2023

You're cleverer than you look.

JJH · Mar 18, 2023

I once had a r100/7 with a 15 inch rear rim laced to what was ornigaly an 18 inch something to do with a sidecar. It had a Citroen Diane back tyre on it. JJH

AnotherGSGSGS · Mar 18, 2023

A 15" motorcycle rim is near identical diameter to a car 15" wheel so it means you can easily fit car tyres to bike wheels which are obviously better for sidecar use. Beyond this motorcycle wheels are slightly larger so seating a car tyre over a motorcycle wheel bead needs a lot of pressure!

JJH · Mar 18, 2023

I thought 15?inches was 15 inches. You live and learn. JJH

jackassdave · Mar 18, 2023

what about lacing an 1150 gs wheel to a airhead hub which is what im in treated in

AnotherGSGSGS · Mar 18, 2023

A 17" car wheel is something like 16.9" and a bike wheel is something like 17.2" the difference isn't a lot but it's enough to just make things a bit 'tight' I tried fitting a 175/17 car tyre onto an RT cast rear for the sidecar outfit I had. At about 60 or 70psi I gave up as the tyre wouldn't move over the bead. I think it probably needed about 100psi+ and lots of lube!

AnotherGSGSGS · Mar 18, 2023

jackassdave said:
what about lacing an 1150 gs wheel to a airhead hub which is what im in treated in

There is no reason why you couldn't lace a 4 bolt para hub to an 1150rim so far as I can tell. I think the nipples are the same size.

All the wheels I've built have been completely central. I understand that to lace a R1150gs rim onto a 4bolt para hub you will have to offset the rim so in the calcs you have to correct for that and then have your spoke size as an average of the two different lengths.

As for 3 bolt monos I don't know. You'd have to drill the hub holes out to take the same nipple type as the 1150 and I don't know if there is a enough meat in the hub for that.

JJH · Mar 18, 2023

AnotherGSGSGS said:
A 17" car wheel is something like 16.9" and a bike wheel is something like 17.2" the difference isn't a lot but it's enough to just make things a bit 'tight' I tried fitting a 175/17 car tyre onto an RT cast rear for the sidecar outfit I had. At about 60 or 70psi I gave up as the tyre wouldn't move over the bead. I think it probably needed about 100psi+ and lots of lube!

100psi? That’s going to launch it into orbit. The tyre is going to give before the bead hops up to where it’s sabosed to go. Lubrication. JJH

Stirlingmoz · Mar 19, 2023

I’ve done the 18” front rim onto a rear hub thing.

I had the paralever hub machined to fit a monolever bevel drive.

This deffo required the rim to be offset to get it in line with the centreline of the bike.

Stirlingmoz

lacing an 18 inch rim onto the 17 inch gs hub

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getting away with it so far!

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