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2004 TTR124 lace 19" rim onto 17" brake drum hub

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I have been through this site and found guys swapping out the big 19" front wheel down to the 17" wheel with lots of detail, etc.

However, I have not found any really good information on the swap from 17" to 19".


I bought a 2004 TTR125 that was partially in a box and put it together and the kids have been riding it. I now have a bunch of money into this bike as many parts were missing in the box, where as the bike was supposed to be complete. Kinda got ripped of buying this bike. But it is what it is now....


The steering feels very twitchy. So I got looking at this more and have discovered that the bike has a 17" front wheel and a 16" rear wheel.


This is not factory it seem, as typically a big wheel has 19"/16" and the small wheel is 17"/14"

But I have 17"/16"

The 16" rear fits into the back swing arm just fine. No issues there.


I think the smaller front wheel is causing the front forks to be too vertical making the steering twitchy.


So I want to swap out the front tire for a 19", but am not really interested in swapping forks and brake systems.


What I want to do is lace on a 1.4-19" rim onto the 17" brake drum hub. I have all the clearances required for the larger wheel.


Has anyone done this ?


The questions that come to mind are?


1) does the 19" and 17" have the same number of spokes?


2) what spoke length would I use and where could I get the required spokes?


3) The spokes are at different angles on the two different rims. I simply cannot add on 1" to the 17" rim spoke length due to angle of the spoke. However, doing some simple geometry calculations I could probably come up with a spoke length. Where could I order spokes by lengths as opposed to bike specific ?


4) I understand Yamaha designed a disc brake for the larger 19" wheel, and the drum for the 17" wheel. This might be a breaking issue due to wheel size. But at the speeds and terrain my kids ride there should be no issues.


So, Has anyone done this ? Re-lacing to a 19" rim is the way I would prefer to go If I can get this to work,


If re-lacing the 19" rim onto the 17" hub is not a possibility, I guess I need to swap out the wheel and hub, meaning a disc brake system, etc. Do I really need to swap out the front forks or will the disc brake mount onto my small wheel drum brake front forks. There does appear to be extra bolt holes on the forks. I am hoping those are for disc brake ? Then its finding all the parts !


Help with this is greatly appreciated.

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Well I think I answered one of my own questions...


the forks are definitely different for the disc brake set up on the big wheel.


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