I will be very specific so that it is as helpful as possible to anyone looking at these.First the bike it went on is a Schwinn signature series MESA 20 inch with a 7 speed gear I bought at a local bike shop. I am being specific since Schwinn makes 2 separate lines and I am not positive dimensions are the same. I first checked the frame piece and though i did not use calipers it seemed slightly over 1 inch, that might just be my aging eyes. I then checked and it seemed relatively parallel to the ground. So far so good.Ordered the product and it arrived first thing this morning. Opened it up and all pieces were there. Looking at the shape of the support piece I figured I would want some rubber between that and the frame. I already suspected this and had an old otterbox case I then cut a piece from for each support. I would either find a piece or order the stick on ones unless you want to scratch the bike. Since this is for a 20 inch bike I hope he will use for several years without training wheels, I wanted to protect the finish somewhat.The product seems well made, Looks to be cold rolled stamped and formed steel. The bolts look decent and the nuts supplied are nylon locking type. Keep in mind with nylon nuts you will want to check them often to make sure they haven't loosened. For those unfamiliar with nylon nuts, the nylon is an insert in the nut, the nut is steel. The tires have plastic hubs as you can tell in the picture, but seem sturdy. If they wear out a pair of replacements will still be significantly less expensive than the other geared bike training wheels. I Got these for under $30 shipped with Prime. Others are in the $75 range.Now for the installation. Read the manual. Do one wheel at a time. I did the rail ride first. After I took off the bikes nut and put on the supplied extension nut, both 15mm, I lined things up to set the height. I ended up using the second longest setting on the frame part and the higher of the 2 wheel holes. The supplied bolts are allen head and they come with that allen wrench. I believe the nuts for the frame and wheel are 12 mm but i seem to have a habit of not putting that size back so I grabbed a pair of channel locks to hold the nut as i tightened the bolt. I then trial fitted it again and noticed that the support would be a bit away from the frame even with the rubber in between. So I bent them slightly more than i would need for tension when i put it on. I expected this since these are not bike specific items and honestly if i had removed the washer that was on the bike i would probably not have had to do even this. once that side was tightened up and it seemed as though nothing would move I did the other side. This side did not need to bent, it went on perfectly.Now for the test ride. My son, who is six but hasn't much bike riding time, took it around the block. Part of the reason for wanting training wheels is the speed this bike needs to move to balance with his small size. I could not keep up and he wasnt trying. The wheels worked nicely and though on concrete show no wear. I have no idea of long term reliability since I got them today, but if they fail fast I will update.

This is a hard to find product...training wheels to fit a 20 inch mountain bike. The instructions could use a translation proofreader, but there's not that much to installing them. They worked fantastically until our tall child finally mastered riding without them.

Easy to install, sturdy, good value for the money at $30 when all competitors for rear-derailleur-friendly stabilizers are $60-$80 or more. The instructions leave a little to be desired, but it's a very simple installation so that's OK. My only complaint is that my set arrived with some hardware missing. It had the most critical piece (the axle hub extender for the gear side), but was missing a screw and locknut that holds the adjustable pieces of the stabilizer arm together (should have had 2x screw and 2x nut, but mine only had 1). A quick trip to Lowe's (or Home Depot or whatever is near you) and I am in business. For anybody who comes up missing the same items, they are M8 x 1.25 thread and the screw has a 16mm length.

Pros: extremely sturdy, very good materials usedCons: one was badly warped, even if okay will not fit a lot of bike framesSee my picture, which honestly doesn't quite do justice to how crooked and warped the one side was. Supposed to be at a 90 degree angle but more like 120. my husband had to whack it with a mallet to get it to sorta fit on the bike. Even so the supportive extra bracket nubbin (don't know what else to call it) is setup only to work with a very narrow spindly frame. I didn't return it only because I had ordered it far enough before that I thought I was out of the eligible return period.

we like the product but had some problems. The nut we took off didnt fit the extender. had to go to the local hardware store to find nuts to replace them. now i think we are good to go

Absolute junk. The fasteners were junk, the arms didn't line up with our bicycle.The hub/axle hardware sheered off, ruining the axle nuts that came with the bike. I had to research and order the correct size replacements.Avoid these.

These do not fit on the huffy rock it 20” bike. I did bend the arm and brackets but it still is not a great fit and I would not recommend for that bike. The wheels also seem flimsy, my son doesn’t want to try to ride it yet so I can’t speak to whether they will hold up or not.

Bought the bike before I realized I would need special training wheels. Looked at several but these appeared well build and not too expensive. They are pretty sturdy compared to ones I have seen in the stores and on other children's bikes. Installation was easy and adjusted quickly to the perfect setting for my son's bike.

Very nice , fits well , exactly what I need for my son’s bike

Wheel screws need a double nut to properly lock the screw in place. (to avoid nut/bolt unscrewing)Otherwise, a perfect product.

Value for money

Fir 32 years old and does not know how to ride a bike, it’s my life save😁🤦🏻‍♀️quality perfect and the size adjustable I used it for big bike

Missing parts