Yamaha MT/R125 wheels on DT



  • Hi again, back with another stupid idea that I'm trying to put into practice 😂
    Basically I'm building my Dt up from frame and engine this winter, YZ 426 forks and triples, MT 125 17" rims, bigger YZ calliper on the front etc. Front triples and forks are now ready to be put on since following the amazing Calums spacer guide (which was an absolute godsend). Just painting the triples before fitting it all together, but some super cheap MT wheels came up, literally a third of the price of wr sm wheels, and I think they will look more unique.
    Here's the problems I've come across so far:
    Rear axle is completely different, and way smaller than the standard hollow Dt axle. I've turned down my own custom axle to make the standard caliper work, also allowing the axle to sit correctly in the swingarm and be the correct length. A collar also needs to be made to go on the other end of the axle however.
    Completely custom spacers need made on either side, and the brake disc will be completely out of line, and standard MT rear disc is actually slightly bigger and won't fit in the Dt caliper 😬
    However sprocket seems to be aligned perfectly when wheel is dead centre, but I will have to confirm this once I've made my spacers. This is all I've gathered so far for the rear wheel setup, I'll update this as I go along, I've not even considered the front axle yet as it'll be an absolute nightmare to do with the YZ forks 😂

    Long story short, do not attempt this conversion unless you have a lot of time, materials and access to a good lathe.
    Even if you do have all this, don't be a tight arse like me and just buy the WR or DTX sm rims haha.



  • @glynn123 I would have used the DTR spindle and simply replaced the bearings in the wheels with ones that have a slightly bigger diameter and a spiggot ring if necessar.

    Interested what you do with this, I know Shaunyboy on the old forum run R125 wheels. Ended up using Yamaha R125 brakes iirc but with stock dtx forks.



  • @calum Sadly the new shape MT/R125 rims have a smaller bearing outer than the older models, the bearings are both the same size front and rear, which is alot smaller than the standard DT one. It's gonna be a nightmare to setup but I'm excited to see the result.



  • Here's some pictures showing the axle comparison, aswell as my custom axle and the wheel mock fitted on the bike.
    http://imgur.com/a/NLB31

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  • Oh wow okay, what's it like for strength then?



  • @calum should be pretty strong as its solid bar and the standard Dt is hollow, I made mine out of a high strength aluminium but I'm thinking of re making in steel once I've done my spacers.



  • @glynn123 I'll have to take your word on that to be fair as I wouldn't know how much it can take.



  • @calum I reckon a good aluminium axle could stand the force no problem due to how it's clamped, however I'd be abit happier having it out some nice steel so will probably do that. I could do some calculations to work out the force put on the axle where the bearings sit. But It wouldn't account for jumps etc so not really relatable. One thing I know mind is that it wouldn't be fun losing the back wheel haha



  • @glynn123 so I made my brake caliper bracket out of ally. Was told to keep an eye on it. That has been sound



  • @calum I reckon I'll be doing the same on my build, need to make an adapter to use the standard wr 426 caliper on the 290mm r125 disc, sadly I can only buy an adapter for 270mm or 320mm discs 😢



  • There's been abit of reconsideration with the build, the rear end was going to be a nightmare, disc was so much out of line that a hub centric spacer would be needed, and one I got the opertunity of a pair of Dt hubs laced onto almost immaculate saxess rims with tyres and discs for £100 I couldn't turn it down haha. Pulled the new Michellin pilot street off the R125 rear wheel and swapped it onto the sm wheels, since the rear was on the limit anyways.
    Will be updating the build as it goes, likely in another thread.
    Cheers Glynn



  • @glynn123 Yeah man nice. Saxxes rims are sweet too

    I have seen the R125 wheels done, but nothing was going to be easy and it would have been an uphill struggle.



  • @calum yeah, basically my problem was starting the build too late in the winter, by the time I faffed about and got the forks done it was the end of January, my plans to have the bike on the road mid March and with the amount of manufacturing left to get the r125 wheels working, along with only being able to work on nights meant this likely wouldn't happen, and I am eager to have the bike on the road and well tested to do a memorial ride for a fallen rider early April.
    I seen the bike which had used r125 wheels on here, looked like a very nice job, in fact it's on eBay right now with a couple days left and only at about £150
    He used the older shape r125 wheels, which have different spacing and bigger outer bearing size, so I reckon a bigger bearing could be fitted to run the standard Dt axle. But basically the swap was a minefield of problems, and after doing the forks and many other bits on my bike I just wasn't in the mood for it this year, besides that the sm wheels I bought are in better condition and should be stronger.



  • @glynn123 Nah mate fair enough. It took me 18 months to get my DT rolling and consequently never used it. So sounds like a great plan.


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