24.0R Convert 19" to 18" wheel

[studioab]

Hi guys,

Instead of mounting Shinko 241 19x3.5 tire, I really would like to convert rear tire to 18", it will allow me to find better options for rear tires.

I'm aware of rear wheel conversion kit, but it is 17" and selection of tires is very limited, on top of that OSET doesn't have them in stock.

Here is what I found on US Ebay:

https://www.ebay.com/itm/WM1-1-60-X-17-36-hole-Akront-Italian-style-flanged-alloy-vintage-motorcycle-rim/164154392242?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D225074%26meid%3Dd1673bbf4ee14b7aabf24322216eb53d%26pid%3D100167%26rk%3D1%26rkt%3D15%26sd%3D163655745238%26itm%3D164154392242%26pmt%3D0%26noa%3D1%26pg%3D5411%26algv%3DDefaultOrganic&_trksid=p5411.c100167.m2940

This rim is 18" x 1.6 x 36H $89

I will only need to find 36 x 12mm spokes. Do you know which spokes will fit? Do they come in standard sizes for 18"

Please let me know what you think before I place an order. Thanks

[sectionone]

That ebay rim is 17". The Oset 17" rim is narrower than 1.6" I got mine from https://mototrialsport.com/

It came as a complete wheel with tire installed and I got the option of bracket and sprocket for quick wheel swap. Pricey at $400.

I couldn't  find a source for the rim to build my own. It uses bicycle spokes so I don't think a motorcycle rim would work without drilling the hub? The only decent 17 inch rear tire is the Vee Rubber trials tire that it comes with. Not that great with harder rubber than a real trials tire and packs with mud easier. The tire says radial, tubless but the wheel has a rimlock.

You should check if an 18" trials tire will rub on the chain. I imagine the extra weight will rob power. 

A guy named Felix Popoki in Hawaii builds 17 and 18 inch wheels for the Sur Ron. You can ask him for his rim source or maybe he can build one.

https://thumpertalk.com/forums/topic/1313021-sur-ron-whos-got-one/page/10/#comments

[studioab]

4 hours ago, sectionone said:

That ebay rim is 17". The Oset 17" rim is narrower than 1.6" I got mine from https://mototrialsport.com/

It came as a complete wheel with tire installed and I got the option of bracket and sprocket for quick wheel swap. Pricey at $400.

I couldn't  find a source for the rim to build my own. It uses bicycle spokes so I don't think a motorcycle rim would work without drilling the hub? The only decent 17 inch rear tire is the Vee Rubber trials tire that it comes with. Not that great with harder rubber than a real trials tire and packs with mud easier. The tire says radial, tubless but the wheel has a rimlock.

You should check if an 18" trials tire will rub on the chain. I imagine the extra weight will rob power. 

A guy named Felix Popoki in Hawaii builds 17 and 18 inch wheels for the Sur Ron. You can ask him for his rim source or maybe he can build one.

https://thumpertalk.com/forums/topic/1313021-sur-ron-whos-got-one/page/10/#comments

Thank you for the tip. According to these blueprints OSET 17" rim is 1.6".

Rim that I found on Ebay is  WM1 1.60 X 17 - 36 hole newly made Akront / Italian style flanged alloy Measures 1.6875" inside bead and 2.25" outside.

I also found another one for cheaper 18" x 1.4" x 36 https://www.ebay.com/itm/Alloy-Rim-1-4-X18-36-holes-Non-Flanged/232806251003?hash=item36345579fb:g:gZQAAOSwW8RbIsqN

I agree, the tricky part is where to find spokes. OSET uses in 17" rear wheel - 36 x 12G x 198mm with 13mm nipples. After a lot of research I found a guy how can make custom spoke set to size https://www.ebay.com/itm/264937086310

Now is the questions what is the right spoke length for the 18" wheel, if my math is correct based on (17" rim / 198mm spoke) (19" rim / 221mm spoke)  the 18" rim should have 209.5 mm spokes

Let me know what you think

Edited November 20, 2020 by studioab