Bicycle Mechanics - 29" Spoke Tension

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View Full Version : 29" Spoke Tension


FatBomber
03-10-08, 11:11 AM
I have a set of WTB LaserDisc Trail 29er wheels and I'd like to take good care of them.

In an effort to facilitate long use I have purchased a Spoke Tensionometer (Park TM-1). I already own a truing stand.

I spoke with WTB and they told me to shoot for the same tension on both sides of the wheels of approximately 110kgf. I thought the numbers are supposed to be different for drive on the rear and disc on the front but he assured me this was not the case here.

1) Is that correct?
2) Upon using the TM-1 I have found spoke tensions all over the board ranging from 61kgf to 122kgf. (The rear wheel is a little out of true.)
3) Should I remove the tire when truing and tensioning the wheel? Will I achieve better results this way?
4) Is there anything else I should take into consideration?


kramnnim
03-10-08, 09:20 PM
Due to the dish of the wheels, one side normally has more tension...but if they somehow end up the same, and the dish is correct...great.

Removing the tire makes it easier to see what you're doing, especially when you're checking the "up and down" roundness of the rims...

markjenn
03-10-08, 09:44 PM
Some folks recommend slightly higher tensions on the rear vs. front (for example, 100 on the front and 110 on the rear). And you always try and reach your target tension on the side of the disk with the shorter spokes (drive side on rear, disc side on front) and accept whatever you get on the other side. On each of the four "wheelsides", you're looking to get everything within 20% of the average for that wheel/side.

- Mark


BCRider
03-11-08, 12:32 AM
I seriously doubt that you'll ever get all the tensions equal and have a round and true running wheel. But that sort of wide range sounds like the wheel could benifit from a good builder slacking them off and redoing the truing from basically scratch.

I tune by sound. I must admit though that it would be interesting to have a guage like that and "ping" some spokes and then test them to figure out just what the tones are telling me.

FatBomber
03-11-08, 08:18 AM
I also true by pitch, but I'm a big time tool-junkie, so it was an excuse to get another tool for the rollaround.

markjenn
03-11-08, 12:10 PM
If you want to be scientific about it, download the spreadsheet on the Park tool site, enter all your readings of the tensionmeter and it will do all the calcs for you.

- Mark

blamp28
03-11-08, 09:26 PM
If you want to be scientific about it, download the spreadsheet on the Park tool site, enter all your readings of the tensionmeter and it will do all the calcs for you.

- Mark

I use that graphing Spreadsheet for my work many times. I like how it illustrates the dynamics of the wheel.