My son wrecked his 125cc Coolster and bent the front rims and so began the quest for new ones. I found what looked to be a direct replacement on the Internet, 16x8x7 with a three bolt pattern. I went to mount them and discovered the holes on the rim did not line up with the studs. I contacted the vendor I purchased and he stated the holes on the rim are 70mm apart and he has nothing smaller. My next trip with to the Coolster web site. I went to their parts area and found a rim with all the demensions listed. It states that the distance is 2.7" which converts to 68.58mm. That explains why they don't fit. My problem is I can't find anybody that sells rims that are less the 70mm and I really don't want to pay Coolster $80 a pop when I just bought two for $70. Any ideas?

 

have you looked on your local craigslist website for non running quads or parts? you may be able to pick up a "junk" one for a little bit of nothing. or there's always ebay & the thrifty nickel want ads. i peruse through CL quite a bit and there are "junk" quads (what people think are junk because they don't run), for usually less than $100.plus you may get tires....other than that, sorry.....

 

So they didn't line up with the studs... But how far off were they? Are we talking something like the thickness of a dime in radius? Or something much larger?

China does everything in metric. Thus the spec of 2.7 inches is suspect already (I'm assuming this is bolt circle radius). I also note the fact that it says 2.7 inches and not 2.700 inches, which implies an accuracy that it good to only 2 significant digits (like somebody perhaps measured it with a ruler).

70 mm is 2.76 inches, which in terms of radius is a difference of only about the thickness of about 12 sheets of paper. Are your rims only missing by that much? Or is there a much bigger difference?

I don't know what the standard rim dimensions are, but it seems really strange that there would be two standards so close together...

 

Probably the thickness of a dime. It wasn't much but only one stud would go through. I agree that 2.7" was probably a ruler measurement but that is what they have listed on their website which is all I have to go with. That was the distance from the center of one hole to the next. 70mm versus 68.58mm if their measurement is accurate. I have to ask with that little of a difference can they be drilled out or would that create to much play?

 

On my quad the rim has a large center hole that fits over a shoulder on the brake drum. That insures that the rim stays centered as long as the lug bolts are tightened up. Is your quad setup the same?

Even so I would be leary of the rim rotating (slipping) on the drum during braking and acceleration in enlarged holes - working at loosening the lug nuts as you go down the trail. If it were me I would drill out the holes to fit (but also making sure that a shoulder on the rim closely mates with the hole in the rim insuring wheel/axle concentricity). Then I would add proper diameter flat washers (1/8" thick) under the lug nuts and weld them to the rim.

 

The rear has disc brakes so no my setup is a bit different
It has a center stud which takes a cassle bolt so I'm not so much concerned about the tire coming off as I am the slipping you referred to. The other thing I've thought about doing is taking the rims to a shop along with rear hub and having them drill and tap three new holes but I'm not sure what that would do to the integrity of the rim. If I could figure out how to attach a picture or insert it into the message I could show you what I'm talking about