My son got a Mongoose Mastif bicycle for Christmas. I’m attempting to assemble it, but I running into a huge problem. I can’t get the front wheel into the forks. The fork seems to be to small to allow the axle to slide into the mounting brackets. Am I nor seeing something or should the front wheel basically just slide onto the fork?
I’m guessing there is a manufacturing problem here. I hope I’m just an idiot, because I hate to have to take it back. Had anyone here assembled this bike? If so, any issues with the front wheel?
Just have someone pull the forks apart far enough to slip the axle into the slots. Shouldn’t be hard. How much more clearance do you need? There may or may not be a set of washers that should be on the outside of the forks.
I can’t really tell what the problem might be. It seems to be an old-fashion nut on axle design as opposed to a quick release system.
Now if the nuts are backed off quite a bit, but the axle won’t pop in the drop-outs, it’s possible that the front fork got bent in shipping. Another possibility is that the axle wasn’t assembled properly and the axle nuts are too far outside. If this is the case, the axle should be loose with a lot of play in it.
Could the disc brake be the issue? Sometimes they don’t slide in properly.
After spending a few hours trying to figure out the problem in positive the forks either were not made to spec or were bent inward during shipping. There is absolutely no way this axle is going to fit in the forks. I’ll call mongoose tomorrow and see what they suggest.
We purchased from Walmart and I decided to assemble the bike myself instead of having them do it. I figured I would know it was built right if I did it. So much for goods intentions! Thanks for the replies.
One of these bikes? Hard to tell from these photos but looks like a standard (but extra wide) fork. Should be a simple matter of loosening the two nuts on the wheel axle (one on each end) and sliding the fork onto the axle, then tightening the nuts. By how much is the fork too narrow?
Yep, that’s the bike. It appears the forks are too narrow by about 1/2". Looking at it more today it almost looks as if the disc brake won’t clear the fork tube even if I could get the wheel on. You are right, you should be able to just loosen the two nuts and slide the wheel on, but isn’t happening in this case.
Is there something asymmetric ? are the bolt areas bent inward ? Straighen up something that is bent …
But I don’t think 1/2" is a big problem … just force the issue.
The spokes of the tyre make an inclined plan… a ramp…
Just put something solid on the tyre, and make that a nice smooth hard ramp…
and then as you push the tyre in, you force the forks apart.
It sounds like a fork for a normal width wheel was fitted instead of the one needed for these extra wide wheels. I’d stay well away from Wal-mart and go to a proper bike shop. But, holy shit, a kid’s bike that weighs 43 pounds? I can’t see that being much fun at all.
I called mongoose and they agreed that the fork must have been bent. They are sending a new fork out. I have to give them credit, they are sending it overnight delivery. I should get it in a few hours, I’ll update if this fixes the issue.
Especially since replacing a fork is not a trivial task, and may require special tools depending on the type of headset.
ETA: Just realized it’s an aluminum bike, so the above may be bad advice. Bending aluminum is not recommended (bending it back and forth would weaken it).
Update: well, the story continues. Mongoose sent us a new fork and it works perfectly. The wheel slipped straight on the way it should. The bad news is to install the fork the disc brake cable needed to be routed through a holder in the fork. The only way to do this was to disconnect the cable from the caliper. To do so you needed to uncrimp the end of the cable. This of course caused the cable to unravel, making it unusable.
So, another call to mongoose and they are sending out a new brake cable. Unfortunately it won’t be here until Tuesday because of the new year. I have to give props to my son, he’s handling the disappointment well and isn’t upset. This was his big Christmas gift.
I’m so sorry that your son has to wait for his present. He is definitely getting good a lesson in patience. That may be worth more than the cost of the bike.
I’ve gotta think that the fork didn’t work because of a manufacturing defect.
Having abused bikes in many shameful ways and never bent a fork, it doesn’t seem like it could have happened in shipping, especially without other apparent damage.
I’m impressed with the customer service reported.
The new cable will probably need to be cut down after installation.
I hope you have some suitable cutters.
Definitely try a practice cut or two further down the length of the cable to make sure your cutters work or you’ll have a mangled mess of pokey needles.
And there’s no reason to wait until the cable arrives to ride.
Back in MY day, it was customary for BMX bikes to have only a single caliper brake in the back.
And most kids learn to ride on bikes equipped with a coaster brake on the rear wheel and nothing up front.
Update: The replacement brake cable came today, earlier than expected. Took about ten minutes and the bike was assembled and my son finally got to enjoy his Christmas gift!
Thanks to everyone who replied and special thanks to Mongoose for their quick response to the problem. Great customer service.
