Replacing the chainring

[Ccross]

I could use some advise on replacing the chainring on my rad rover.
Since most of my riding is on steep hills I would like to have lower gearing.
The loss of top speed is not a concern.
Problem is I have no idea if the bolt patterns are a standard size , or chain size, number of teeth.
I am thinking it should be a easy part swap if I buy the right chainring .
Anyone know where I can find this info?

[Altema]

You could probably find a matching chainring for the Rad bolt pattern, but it may be simpler to just change the crank arms and chainring as a set. They have several on Amazon, and one of them is listed below which gives you a choice of sizes with 32/34/36/38/40/42 teeth.

https://amzn.to/2OVfQiZ

[JTK77]

I have upgraded to 52t chainring and 8 speed 11-42 cassette. Good from slow speed up to 40mph.
Note. I have changed to G062.1000
DC (free hub version). Thats why cassette.

[Tony]

Thanks for the reply JTK77. is this on a Rad Mini ?  Tony. 

[JTK77]

Thanks for the reply JTK77. is this on a Rad Mini ?  Tony.

Rhino (/Rover).

[Tony]

The cassette fitted is 11-34 on the mini.  So a bigger front chainring is the way to go, and I presume a longer chain is this correct ?

[Altema]

The cassette fitted is 11-34 on the mini.  So a bigger front chainring is the way to go, and I presume a longer chain is this correct ?

A longer chain would be required for a larger chainring.
The original poster needs lower gearing for climbing hills however, so in that situation, they would need a smaller chainring and a shorter chain.

[morrison10]

I changed the front chaining to 56T without having to change the chain length on my RAD MINI.  Works great and can now keep up with the motor at speeds over 20 mph.

https://amzn.to/3v2ba9V

[Tony]

Thank you for this information. I have found these are available in the U.K.

[Tony]

Do I need a puller / extractor tool to remove this ? 

[Eric7]

It seems all the recommendations for chainrings involve buying a new crank with a new chainring.

Is it possible just to buy a chainring without a crank arm to save some money?  What hole pattern should I be looking for?  Any suggestions with an amazon link?

Thank you for any information.

[Radio Runner]

The bolt pattern on my RRunner is 130mm. I think it's the same on a few others but not sure since I don't own them. I swapped out my 52t for a 48t. Lots of hills here as well.

[turtle44]

FYI:  I bought a SHIMANO 105 5700 52t 130mm chain ring for my Radwagon 4.  Some things to consider for anyone who wants to do this:

1)  The 52t chain ring is larger diameter than the stock RW4 46t ring.  The larger chain ring mimics the diameter of the chain guard plates.  The chain will therefore end up outside the stock chain ring plates by the thickness of the chain.  (Watch the cuffs on your pants.)  It still works, but it looks goofy and defeats the purpose of the chain guard plates.

2)  The stock RW4 granny gear is very large so that the derailleur does not work well with the larger diameter.  Shifting in and out of 1st gear (large rear sprocket) caused the chain to bind up and prevent the pedals from continuing rotation.  The Ebikekit / Bolton freewheels eliminate the large gear and this might work although I haven't tried it yet.  Also, it may be a solution to lengthen the chain.  I haven't tried a fix yet.

3)  If you have a full battery, or especially if you have an upgraded controller/motor, the top end speed will cause the stock gearing to be an uncomfortably fast cadence.  I went to the following website to try to calculate what gearing I'd like to have at https://www.bikecalc.com/speed_at_cadence.  I used 24" tire diameter and 11 teeth on the rear sprocket to find the delta between 46 and 52 teeth.  46t, 70RPM = 18.95mph.  52t, 70RPM = 21.5RPM which let me know that the 52t would be good for the stock high gear.  Unfortunately I didn't think about the chain length.  Weekend project I guess.....

Hope that helps someone.

[Eric7]

The bolt pattern on my RRunner is 130mm. I think it's the same on a few others but not sure since I don't own them. I swapped out my 52t for a 48t. Lots of hills here as well.

Thanks for sharing. I have a micrometer and measured. On my Rad Mini ST, the distance between bolts according to my calculations is 64.65 mm.  Therefore I conclude my Rad Mini ST uses a 110 BCD chainring.  I just thought I share.  Everyone, please make your own measurements and don't take my word for it.

[Radio Runner]

110mm on the mini is good to know. I wish my RR was 110 instead of 130mm. 110mm has a lot bigger range of options since the bolt circle is smaller. I may swap out the cranks to 110mm at some point.