Thread size for rear rack mount holes on RadRover 2018?

[echeng]

Hello, everyone! I just received my RadRover, and love it so far. I ordered a Topeak Uni super Tourist Fat Rack, but have been having problems finding a bolt that can be used to attach it to the 4 mounting holes. The Topeak comes with M5 bolts, which are too large, and M4 bolts are too small.

Rad Power Bikes support said, "As for the screw dimensions, they are standard M4x0.7mm screws, but I am not positive, unfortunately. If you take it in to a local hardware store they will be able to get you a definite answer.", but M4 bolts slip right through. I can't bring my bike to a local hardware store anytime soon.

Can anyone here verify? Thank you!

 

[mrgold35]

I have the same rack on my two 2016 Radrovers. I used the M5X15mm bolts that came with the rack. I had a little issue getting the bolts started and I think it is because there is paint in the threads. I had to use some "elbow grease" to clear out the paint using the M5 bolt. Then I mounted the rack and re-used the bolts. I also had to add some blue med strength Loctite (paste in a tube version) about a month later because the M5 bolts started to get a little loose over time. They are staying properly tq after +2 years.

I don't think Rad would change the bolt sizes for the 2018 Rover?

 

[MadManMark]

As an alternative idea -- and I am only thinking about this, haven't attempted -- I am considering destroying my Topeak MTX rack (taken off my human-powered bike) in order to salvage just the track, and then try to figure out how to attach that to the top of the built-in rack, either somehow clipping onto it, or making use of the bolt holes on the top. But I haven't gotten around to figuring it out yet (only had my RadCity for about a month).

Not an answer to your question, but maybe something to think about as an alternative, "outside the box" approach. My reasoning is that if I can just figure out how to do this, it will not only be more elegant looking & perhaps sounding (less rattle from racks knocking against each other?) but also a little less weight and a bit more stable.

Good luck, I will be interested in what you do regardless.

 

[echeng]

I have the same rack on my two 2016 Radrovers. I used the M5X15mm bolts that came with the rack. I had a little issue getting the bolts started and I think it is because there is paint in the threads. I had to use some "elbow grease" to clear out the paint using the M5 bolt.

Thank you! I'll use M5s with force, and try not to cross-thread. I was worried because of the Rad Power reply, which said that they think it is M4.

Regarding the getting MPX onto the Rad City, it might be worth asking the manufacturer of this MTX rack adapter to see if one is available for the rack on the RadCity? (Link Removed - No Longer Exists)

 

[rich c]

Consider using an M5 tap to CUT out the paint, instead of using force on the bolt. It won't take a high quality tap to just cut out the paint or powder coating.

 

[mrgold35]

Topeak does make a MTX DXP bag with velcro instead of the Quicktrack bottom. When I ordered my two MTX bags on eBay a week apart, I didn't notice one was velcro attached and the second was Quicktrack. Both worked equally well with the Uni Super rack. I switched the velcro MTX bag to the wife's Radcity Step-thru and purchased a 3rd MTX rack back with the Quicktrack bottom.

What I like about the Velcro MTX bag is I can use it on any bike with a rack; while, the Quicktrack bag can only go on my Radrover.

 

[echeng]

Thank you, everyone, for your help! The M5 screws went right in, with a little effort, and the rack is on. I might move it forward a bit, but the bike is so heavy that it's probably fine back there.

 

[Dads]

HI there I also have the Topeak Super tourist fat,and installed it on my2019 Radrover step through.I had no problems with the M5 x15 bolts except for paint.I bought another Topeak rack for my wife’s 2021 Rad mini step through 2.The M5x15 bolts it came with,go right through the holes.Now I wonder why Rad went with a different size,and does any one know what size they are.Can’t get any info from Rad site.
Update for the Radmini ST 2.I picked up some M5 washers and nuts for the Topeka rack,bottom hole.While at the store picked up a couple M6 x 15 to see if they would screw into bottom rack hole on Radmini.Was I surprised when they screwed in .So the Radmini ST 2 has different size threads than my Radrover ST.I tried putting the M6 threaded bolts through the bottom holes of Topeka rack,and they won’t go through.So do I drill out the bottom hole of rack to accomadate M6 bolts that will screw into bottom holes of The Radmini ST,or use the M5x15 and use nuts and washers to tighten.I think I will use the M5,S and nuts.
Thanks for listening