Bicycle Mechanics - How to determine spoke tension specs

I've decided to build my next set of wheels the right way and got a spoke tension meter. My question is, how do I know what the proper spoke tension is supposed to be? Is this determined by the rim manufacturer or is it found from a combination of the spokes/rim/hub. Is it calculated or just estimated within a range?

I understand the concept of average spoke tension and allowing for a 10%-20% variation on one side of the wheel, just want to know what tension should be or is limited by.

My planned build is: Kinlin XR-300 rim, AC 205 hub, 24 spokes. Don't know what spokes yet, probably Sapim CX-ray. 2X pattern

Also may build a PT hub to another Kinlin XR-300, 24 spoke.

Based on what I've read, the rim will be the limiting factor in spoke tension. I just built up a set of wheels for my new bike using IRD Cadence rims (similar to Kinlin XR-200s) and tensioned the front to 110 kgf and the rear to 120 kgf after posting here and receiving advice that my initial tension of 90 kgf was likely too low. I had based my tension numbers off American Classic's spoke tension recommendation of 90-110 kgf for their Sprint 350 wheels (which I have on another bike). But, those are non-eyeleted rims. I'm using 32 spokes with a 3 cross pattern so I didn't feel the need to really crank up the tension. With only 24 spokes, things get a little trickier.

I emailed IRD last weekend to get their recommendation for tension but they still haven't replied and I suspect they won't. I'd be curious to hear what if anything Kinlin recommends. You might also ask some people using the same rims to check their tension. It would at least give you an idea of what to shoot for.

120kgf might be the upper limit for kinlin rims.

general guideline is sticking to around 110kgf.

when you mount a tire, the spoke tension drops because the rim compresses, so once you finish your wheel, mount a tire, inflate and recheck the spoke tension, making sure the spokes don't go below 90kgf

Yep, it's basically determined by the rim's max tension. Going past that can cause the rim to collapse or taco. I bring the rear drive side as close as I can without going over, and the front wheel is generally at about 90%.

Thanks guys. I talked to my LBS and they said 120 was probably the max for the Kinlin rims also. I'm going to contact Kinlin anyway since I'm still waiting for my hub to come in the mail.

Cheers

Post back here what they say since my next build is AC 205 and Micro 58 hubs with either XR-300 or XR-270 rims.

Bring the spoke tension as high as you can; the tighter the spokes, the stiffer and stronger the wheel. I would highly suggest not using Sapim X-rays. You need to use a tool to keep the blade straight, and if you try and keep the blade straight while tightening the spoke at a medium to high spoke tension, the spoke twists and bends where the tool is keeping the spoke straight. DT aerolites twist back into place, but because the Sapim's are so thin and maliable, the spoke actually bends at the twist. The bent spokes must be replaced, and since you can't get a high tension out of them due to this twisting/bending, it sacrifices the strength of the wheel. Go with DT Aerolites or Supercomps instead.

Bring the spoke tension as high as you can; the tighter the spokes, the stiffer and stronger the wheel. I would highly suggest not using Sapim X-rays. You need to use a tool to keep the blade straight, and if you try and keep the blade straight while tightening the spoke at a medium to high spoke tension, the spoke twists and bends where the tool is keeping the spoke straight. DT aerolites twist back into place, but because the Sapim's are so thin and maliable, the spoke actually bends at the twist. The bent spokes must be replaced, and since you can't get a high tension out of them due to this twisting/bending, it sacrifices the strength of the wheel. Go with DT Aerolites or Supercomps instead.

I would think that lubricating the nipples at the rim and the spoke threads would greatly reduce the chances of this happening. I know that I had twisting problems trying to tension my all-DT Revolution spoked front wheel. The problem was removed by adding some chain lube at each spoke hole. Completely removed the spoke wind-up issue I was previously having (part of the reason I initially stopped at 90 kgf).

I had used Spoke Prep and Prolink lube on all spoke threads before lacing the wheel, and then applied prolink on all nipple/spoke joints after the wheel was built and before tensioning. This is my process with every wheel, and I never had a problem with spokes bending before.

Do remember that the left side (non-drive side) of the rear wheel will be substantially lower in tension - if you have adjusted for dishing. While you may have 120kgf on the drive-side, the non-drive will likely to be 80kgf or so. Don't let that spook you. As Sheldon "Wheels" Brown had said - "Just forget about the left-side."

I had used Spoke Prep and Prolink lube on all spoke threads before lacing the wheel, and then applied prolink on all nipple/spoke joints after the wheel was built and before tensioning. This is my process with every wheel, and I never had a problem with spokes bending before.

I've never built a wheel with Sapim CX-ray spokes so I'll bow to your experience. I'm happy that I chose DT Revo's over the Sapims for my last wheel build.

"when you mount a tire, the spoke tension drops because the rim compresses"

I have to ask, how do you decrease the circumference of an alloy hoop? Do the molecules of the alloy actually get closer together? Does the weld get squished?

Post back here what they say since my next build is AC 205 and Micro 58 hubs with either XR-300 or XR-270 rims.

Maybe you're aware of this and willing to deal, but those hubs have some pitiful bearings. You'll be replacing them early and often. I had a pair of Speedream wheels built with them and was not happy. I only weighed 135 at the time, they were not subjected to anything close to rough treatment, QR was never overtightened, yet I only got a few hundred miles out of the bearings. Other reviews have mirrored my experience. Seriously consider other options. This hub's contribution to light weight wheels is outweighed by the sacrifice in durability imho.

"when you mount a tire, the spoke tension drops because the rim compresses"

I have to ask, how do you decrease the circumference of an alloy hoop? Do the molecules of the alloy actually get closer together? Does the weld get squished?

It's true. Increased compression = increased strain = increased molecule 'closeness', if you prefer it in those terms. And the weld is always 'squished' from the moment the spokes take tension.... which is why welds are not necessary. :innocent:

"when you mount a tire, the spoke tension drops because the rim compresses"

I have to ask, how do you decrease the circumference of an alloy hoop? Do the molecules of the alloy actually get closer together? Does the weld get squished?

good question. usually the joint in the rim compresses slightly for rims built with sleeve joints, but I'm not sure why a welded one will compress.

I only have proof that this happens and it's easily reproduced.
for example, you build a wheel and end up with 100~120kgf tension using 2.0mm/1.8mm DB spokes, but when you mount a 23~28mm tire and bring the tire up to 100psi, it makes the spoke tension dip down to 90~115kgf.

so usually, what I do when building a wheel is to build it up to the higher limit, mount and inflate tire, then remeasure spoke tension to make sure they're all within 10% of each other.

...the tighter the spokes, the stiffer and stronger the wheel...
<false (http://www.sheldonbrown.com/rinard/wheel/index.htm)>

Some believe that a wheel built with tighter spokes is stiffer. It is not. Wheel stiffness does not vary significantly with spoke tension unless a spoke becomes totally slack.
However, I don't see anything wrong with making the spokes as tight as the rim will allow.



Maybe you're aware of this and willing to deal, but those hubs have some pitiful bearings. You'll be replacing them early and often. I had a pair of Speedream wheels built with them and was not happy. I only weighed 135 at the time, they were not subjected to anything close to rough treatment, QR was never overtightened, yet I only got a few hundred miles out of the bearings. Other reviews have mirrored my experience. Seriously consider other options. This hub's contribution to light weight wheels is outweighed by the sacrifice in durability imho.
That is a concern of mine. I got a really good deal on the hubs (paid $120 for the set) and I'm hoping that my history of being easy on parts (I weigh 150, but more importantly, I produce very little power :D ) will negate the durability issue. For the life of me, I'd love to crack my Forte Titan hub so my wife will approve of my build, but I can't. Your details worry me, though, and have me wondering if those cheap Novatec hubs on Ebay or EJ's Formula hubs would be a better choice at a small weight penalty. I do know plenty of people heavier and stronger than me who don't seem to have that problem with their 420s, 350s, and Hurricanes. Same hubs iirc. I'll probably just build and cross my fingers, then buy sturdier hubs later if needed.

good question. usually the joint in the rim compresses slightly for rims built with sleeve joints, but I'm not sure why a welded one will compress.

I only have proof that this happens and it's easily reproduced.
for example, you build a wheel and end up with 100~120kgf tension using 2.0mm/1.8mm DB spokes, but when you mount a 23~28mm tire and bring the tire up to 100psi, it makes the spoke tension dip down to 90~115kgf.

so usually, what I do when building a wheel is to build it up to the higher limit, mount and inflate tire, then remeasure spoke tension to make sure they're all within 10% of each other.

So I just now checked my wheel. A 28-hole DT Swiss RR1.1 rim with DT DB spokes. I check the tension on a two pairs of crossing spokes, in two places, 180 degrees apart, on opposite sides of the flange, with tire fully inflated.
All measured 19.5 on the Park gauge.
Deflated tire and remeasured. All measured 20.5.
To be truthful, my initial post was written as more sarcastic skepticism, rather than an honest question. But now the question becomes honest.

These are double wall rims with eyelets on only the inner wall.
Out of curiosity, I measured the exact width of the rim with an uninflated tire mounted, using digital calipers at two different places, once at the weld, once at another spot away from the weld. Both spots measured exactly 19.30mm. I then inflated the tire and measured. The weld measured 19.54, and the other spot measured 19.60.
So the rim width increased with an inflated tire.

I'm glad you mentioned rechecking tension on a built wheel before and after a fully inflated tire is mounted. I hadn't thought of doing this in the past. Funny, I have read a whole lot of books and individual articles on wheel building and can't recall this ever mentioned. Since the wheel's purpose is to be ridden with a fully inflated tire, and inflating does change the tension, it only makes sense to make final measurements with the wheel inflated.

<false (http://www.sheldonbrown.com/rinard/wheel/index.htm)>

However, I don't see anything wrong with making the spokes as tight as the rim will allow.



That is a concern of mine. I got a really good deal on the hubs (paid $120 for the set) and I'm hoping that my history of being easy on parts (I weigh 150, but more importantly, I produce very little power :D ) will negate the durability issue. For the life of me, I'd love to crack my Forte Titan hub so my wife will approve of my build, but I can't. Your details worry me, though, and have me wondering if those cheap Novatec hubs on Ebay or EJ's Formula hubs would be a better choice at a small weight penalty. I do know plenty of people heavier and stronger than me who don't seem to have that problem with their 420s, 350s, and Hurricanes. Same hubs iirc. I'll probably just build and cross my fingers, then buy sturdier hubs later if needed.

The good news is that replacement bearings are very cheap, $10, and require no special tools. And I've never heard of problems with spokes pulling through, so the flanges seem well engineered.
We're kind of in the same boat. I got a good deal on my DT Swiss RR1.1 rim. After buying it, I found a whole lot of bad reviews on the single eyelet version, which mine was. DT Swiss even recalled them. I built the wheel up anyways and keep my fingers crossed as well. The damn things built up so nice and true, it's worth the confidence boost and positive building experience even if they don't last.

Post back here what they say since my next build is AC 205 and Micro 58 hubs with either XR-300 or XR-270 rims.

I will let you know. I couldn't find any direct contact to Kinlin themselves, but I'm going to ask Fairwheelbikes (where I got the rims) and wheelbuilder.com since they both sell and build these rims

Bring the spoke tension as high as you can; the tighter the spokes, the stiffer and stronger the wheel. I would highly suggest not using Sapim X-rays. You need to use a tool to keep the blade straight, and if you try and keep the blade straight while tightening the spoke at a medium to high spoke tension, the spoke twists and bends where the tool is keeping the spoke straight. DT aerolites twist back into place, but because the Sapim's are so thin and maliable, the spoke actually bends at the twist. The bent spokes must be replaced, and since you can't get a high tension out of them due to this twisting/bending, it sacrifices the strength of the wheel. Go with DT Aerolites or Supercomps instead.

Thanks for the heads up... that would have sucked to blow a bunch of money on those spokes and then find that I couldn't build properly with them. I guess the wheel manufacturers that build with those spokes (since they do seem to be popular on built wheels I've seen for sale) have some way around that problem.

DT Swiss it is for me.... I wish I could afford their hubs too

The good news is that replacement bearings are very cheap, $10, and require no special tools. And I've never heard of problems with spokes pulling through, so the flanges seem well engineered.
We're kind of in the same boat. I got a good deal on my DT Swiss RR1.1 rim. After buying it, I found a whole lot of bad reviews on the single eyelet version, which mine was. DT Swiss even recalled them. I built the wheel up anyways and keep my fingers crossed as well. The damn things built up so nice and true, it's worth the confidence boost and positive building experience even if they don't last.


I've actually heard the same about the bearings. There are a TON of replacement ones on eBay. I got a very very good deal on my hubs which is why I went AC.

Urbanknight -- if the AC's don't work out for you go SOUL, forget those Novatec ones. I was talking to Sean at Soul and he told me their new Prodigy hub will be out soon. Their current hubs are pretty sweet too, only $230 shipped for the set weighing in at 273 g (I think). If I didn't get such a good deal on my AC's thats the route I was going to go.

I'm an importer of KinLin rims...but I'll comment on a generic basic - but I'll use KinLin rims as a reference.

Think Araya copy 26 x 1.50 rims with the slight diamond profile. (KinLin RT-6N 3.0mm thickness.)
Think Araya copy 27 x 1 1/4 rims with the bump in the center. (KinLin 5ALM 2.0mm-2.5mm thickness.)

Think Araya copy 26 x 1.50 rims with the slight concave profile - double wall. (KinLin ADHN with 2.0mm thickness).

Think Araya copy 700 x 20c rims with the semi-box profile. (KinLin STTS-21) with 2.0mm thickness.

All of the above rims as is typical with most rims today - including generics - are heat treated - aged - and hard anodized - even in silver.

I aim for 110kgf average tension...some spokes will show 120-122...I don't worry too much. My main concern with todays rims is not so much warpage due to overtensioning...pretty hard to do now unless you are not paying attention...but rather cracking the rim holes.

My experience has been that when you go past 120kgf average tension - rim hole cracking is on the horizon.

Add a single eyelet...will I increase the tension? Nope...but it does help with hole cracking. Add a double eyelet - sure I'll add a few more kgf if a customer wants. I won't lose sleep over it.

KinLin basic rims are hard as hell by the way. They are heat treated, aged and hard anodized to death - even their silver satin finished rims. Some of their single wall rims (RT-6N) are 3.0mm thick and taking up a "dip" caused by a defect can be a pain in the ass. But these rims are as strong as some others 2.0mm thick double wall rims. So I try not to complain...customer's aren't, so why should I?

As to KinLin's lighter weight higher performance rims such as the ones mentioned, and the MX4's that I carry...110-115kgf should not be a problem.

Proceed carefully with KinLin's XR-300 though...deepv via thin walls...aimed at a very low weight of 450g...lighter than a Mavic CXP-33?...they're kinding pushing it. 110kgf may be more than enough for that one. Personally, I prefer the XR240 - just seem a little "safer" in my opinion at 470g.

=8-)





As to other diamond profile Araya copy rims out there...be sure to measure the wall thickness at the center before using. Some are only 1.5mm thick...and are pretty much only reliable for front wheels on MTB bikes. Sheang-Lih (Shining) A-5N is a perfect example.

What nipple length should I use with the XR-300's? 12mm,14mm,16mm??

I would highly suggest not using Sapim X-rays. You need to use a tool to keep the blade straight, and if you try and keep the blade straight while tightening the spoke at a medium to high spoke tension, the spoke twists and bends where the tool is keeping the spoke straight. DT aerolites twist back into place, but because the Sapim's are so thin and maliable, the spoke actually bends at the twist. The bent spokes must be replaced, and since you can't get a high tension out of them due to this twisting/bending, it sacrifices the strength of the wheel.
That has never happened to me. And you're the first person in the ten years or so I've been aware of CX-Ray that has claimed this to my knowledge. I use the holding tool from Sapim. CX-Ray are fine and build up into a great wheel.

Urbanknight -- if the AC's don't work out for you go SOUL, forget those Novatec ones. I was talking to Sean at Soul and he told me their new Prodigy hub will be out soon. Their current hubs are pretty sweet too, only $230 shipped for the set weighing in at 273 g (I think). If I didn't get such a good deal on my AC's thats the route I was going to go.
Thanks. I hope he offers more drillings, though. The hubs I got a deal on were 28h front and rear. I would have prefered 24/28 or even 20/24 with the deeper rim, but a tight budget makes me less specific.

http://www.bikeforums.net/showpost.php?p=7333550&postcount=13

good question. usually the joint in the rim compresses slightly for rims built with sleeve joints, but I'm not sure why a welded one will compress.

I only have proof that this happens and it's easily reproduced.
for example, you build a wheel and end up with 100~120kgf tension using 2.0mm/1.8mm DB spokes, but when you mount a 23~28mm tire and bring the tire up to 100psi, it makes the spoke tension dip down to 90~115kgf.

so usually, what I do when building a wheel is to build it up to the higher limit, mount and inflate tire, then remeasure spoke tension to make sure they're all within 10% of each other.

This is why the final lateral truing and dishing on the rear wheel need to be done with the tire fully inflated.
BTW, my rims (DT RR 1.1) are welded and the spokes show about a 5% decrease in tension after inflating the tires.

So I just now checked my wheel. A 28-hole DT Swiss RR1.1 rim with DT DB spokes. I check the tension on a two pairs of crossing spokes, in two places, 180 degrees apart, on opposite sides of the flange, with tire fully inflated.
All measured 19.5 on the Park gauge.
Deflated tire and remeasured. All measured 20.5.
To be truthful, my initial post was written as more sarcastic skepticism, rather than an honest question. But now the question becomes honest.

These are double wall rims with eyelets on only the inner wall.
Out of curiosity, I measured the exact width of the rim with an uninflated tire mounted, using digital calipers at two different places, once at the weld, once at another spot away from the weld. Both spots measured exactly 19.30mm. I then inflated the tire and measured. The weld measured 19.54, and the other spot measured 19.60.
So the rim width increased with an inflated tire.

I'm glad you mentioned rechecking tension on a built wheel before and after a fully inflated tire is mounted. I hadn't thought of doing this in the past. Funny, I have read a whole lot of books and individual articles on wheel building and can't recall this ever mentioned. Since the wheel's purpose is to be ridden with a fully inflated tire, and inflating does change the tension, it only makes sense to make final measurements with the wheel inflated.

I have no fact, just a hunch, that more pressure on a rim (spoke tension + air pressure) makes the rim more of a perfect circle. (lesser outward bulge between spokes) The less perfect circle made by the rim without that additional smoothing of the inflated tire would be longer and some if not all of the spokes would be stressed more. It takes very little displacement (distance) to make a substantial difference in the tension.

http://www.bikeforums.net/showpost.php?p=7333550&postcount=13

Sampler of Soils...

There's a possiblity you may have received a bad batch of those spokes. Anytime I order spokes from Taiwan - ANYTIME - I get the following in my quotes (paraphrasing):

"310mm Stainless Steel 2.0mm w/ 6.2mm elbow for alloy hubs."

Other thing to remember is that DT Swiss is a metalurgical company as well...formulate their own materials for the bicycle industries - and other industries as well. That aerolite reflects that and of course is a high quality, high-end processed product. So in a way, you are kinda compaing apples and oranges...

...but that doesn't really matter. Those Sapims just like my CNs use a mid-quality formulation and process - and with 6.2mm elbows should work just fine with a little care and support during the truing and tensioning process.

Might want to call around and find out if they are supposed to be 6.2mm or 7.0mm.

Don't be so quick to give up on 'em, call 'em what they are - an alternative to DT - and make 'em work.

=8-)

Wups...sorry...pass it on to Bananawhatever...

=8-)

Here is what I heard from fairwheel bikes about the tension specs on the Kinlin Xr-300 rim

"Hi CF,

There really isn't much reason to put too much tension on a rim. Tension will not affect stiffness, but rather spoke life for heavier riders. I don't see any reason to go above 110kgf on the 300. The rim has no eyelets so a standard alloy or brass nipple is fine, no need to get anything longer.

Cheers

Jason
Fair Wheel Bikes "


So the recommendations earlier in the post were right on