Thru axle versus QR

[Johan Bornman]

Johan I noticed you said nothing about stiffnes, do you think that a thru axle is actualy so much stiffer that you will notice the difference. I mean I swear people think the a quick release is the axle of the wheel which it is not, and by thinking that they say yes its stiffer. How do you notice the stiffnes on a wheel with a shock. By saying its stiifer they must suggest that a quickrelease hub actually have flex on it, so much that you will notice it.

 

Everything you said about the through axle I 100% agree with and that would be the reason I would buy a through axle not because of "stiffness"

Quite observant. Yes, I purposefully didn't say anything about stiffness because I think it is nonsence. I'm very cynical about anything that is supposedly better through the mechanism of stiffness.

 

We dont feel huge twisting (as in turning the steering) forces through the handlebars when we ride a bike. This means that there is no such force. Hold your bike in the upright position with the saddle between your knees and the back wheel between your ankes. Have a friend twist the front wheel with a force that you expect would flex the hub/fork joint. Notice the huge force on your handlebars and tell yourself that you've never felt force like that when riding. So where does it come from? It doesn't exist.

 

Most of these "stiffer" arguments are all post-rationalised. Usually it is just a better design (TA, tapered head tube, hollowtech etc etc) than the original. It doesn't make for great brochure writing to just say, "New, Improved Design." The old one was crap but we tried again". It is far better marketing to say, better, lighter. stiffer, faster, hence the huge emphasis on stiff. The same ad agency that works for Pfizer's Viagra department, I suppose.

 

But back to the stiffness. Most of the flex is hubs was eliminated when front wheels became suspension-firendly. This was the increase in diameter of the hub's centre section. Just compare a 1990s MTB hub with today's. After than, I don't think the TA did anything new. If you analyse the TA, you'll notice that the axle (the part that screws into the fork) sits relatively loose inside the wheel with some play.To me this means that the axle simply provides clamping and the end cups on the wheel provide the support. Some of them are even made from plastic or thin alu. Not steel, not press-fit on the axle. Just a loose, easy affair.

 

Had we really required stiffness there the mechanism would have been far beefier as on DH bikes. Here the axle is usually pinch-bolted onto the fork at both ends or in the case of semi-QR models, screws in on the one side and press-fits on the non-screw side.

 

In summary, I believe we have adequate stiffness even in QR for the little forces the wheel experience. TA is better but for other reasons.

[nishiki]

Quite observant. Yes, I purposefully didn't say anything about stiffness because I think it is nonsence. I'm very cynical about anything that is supposedly better through the mechanism of stiffness.

 

We dont feel huge twisting (as in turning the steering) forces through the handlebars when we ride a bike. This means that there is no such force. Hold your bike in the upright position with the saddle between your knees and the back wheel between your ankes. Have a friend twist the front wheel with a force that you expect would flex the hub/fork joint. Notice the huge force on your handlebars and tell yourself that you've never felt force like that when riding. So where does it come from? It doesn't exist.

 

Most of these "stiffer" arguments are all post-rationalised. Usually it is just a better design (TA, tapered head tube, hollowtech etc etc) than the original. It doesn't make for great brochure writing to just say, "New, Improved Design." The old one was crap but we tried again". It is far better marketing to say, better, lighter. stiffer, faster, hence the huge emphasis on stiff. The same ad agency that works for Pfizer's Viagra department, I suppose.

 

But back to the stiffness. Most of the flex is hubs was eliminated when front wheels became suspension-firendly. This was the increase in diameter of the hub's centre section. Just compare a 1990s MTB hub with today's. After than, I don't think the TA did anything new. If you analyse the TA, you'll notice that the axle (the part that screws into the fork) sits relatively loose inside the wheel with some play.To me this means that the axle simply provides clamping and the end cups on the wheel provide the support. Some of them are even made from plastic or thin alu. Not steel, not press-fit on the axle. Just a loose, easy affair.

 

Had we really required stiffness there the mechanism would have been far beefier as on DH bikes. Here the axle is usually pinch-bolted onto the fork at both ends or in the case of semi-QR models, screws in on the one side and press-fits on the non-screw side.

 

In summary, I believe we have adequate stiffness even in QR for the little forces the wheel experience. TA is better but for other reasons.

Viagra sells itself Johan It definitely makes things much stiffer, as with the TA.

 

I can feel the stiffness (of the TA fork vs QR). Makes perfect sense mechanically as to why as well. On one you have a 20mm bar threaded between 2 points and clamped, the other you don't. I'm sure we could find a fork that has both options and test this. Any takers?

[sometime]

I can guarantee that 98% of all Hubbers would not be able to tell the difference if they were riding TA or QR. You will tell yourself you can but in a back to back 'blind' test you won't know the difference. In terms of safety a QR skewer can still come loose and will not fall out too easily - they're designed that way. Doing Barberton this year I was hearing a noise from my front fork for a while heading down a long, fast, rutted forest road, but was going too fast to take my eyes off the trail. When I did look down I noticed my skewer was loose but the wheel had stayed on. But I agree that a TA gives you some peace of mind in case a skewer comes loose.

 

To the OP if you're buying new then by all means buy a TA but if you can get a Reba in QR at a good price then I wouldn't hesitate and spend your money on NB stuff like wheels and tyres.

 

PS just read Johan's posts and agree 100%.

[nishiki]

I can guarantee that 98% of all Hubbers would not be able to tell the difference if they were riding TA or QR. You will tell yourself you can but in a back to back 'blind' test you won't know the difference. In terms of safety a QR skewer can still come loose and will not fall out too easily - they're designed that way. Doing Barberton this year I was hearing a noise from my front fork for a while heading down a long, fast, rutted forest road, but was going too fast to take my eyes off the trail. When I did look down I noticed my skewer was loose but the wheel had stayed on. But I agree that a TA gives you some peace of mind in case a skewer comes loose.

 

To the OP if you're buying new then by all means buy a TA but if you can get a Reba in QR at a good price then I wouldn't hesitate and spend your money on NB stuff like wheels and tyres.

 

PS just read Johan's posts and agree 100%.

Don't be so sure of that. There are many riders who'll disagree with you on this. I can feel it like night and day. The more technical you take your riding, the more you'll feel the stiffness.

 

But if you are willing to bet on 98%, how about a little wager? We'll need a demo fork that has QR/TA switchability, a nice rocky technical singletrack and 20 riders. Willing to bet your car/house that more than 98% CAN feel the diffs? (Bear in mind only 1 person needs to win the blind test and you lose).

[Motard660]

Are we going to need popcorn for this one again?

 

I got two bikes with TA and one with QR and to be frankly honest never felt any difference between the two while ridding. I will agree the the TA is probably better, but not for the reason of "stiffness". Taking a TA wheel off and back on is mush easier and there is the sense of safety when ridding knowing that the wheel is more secure with TA, but that is that for me! Maybe I am not ridding my bikes hard enough and not taking them to the edge to feel the difference.

[sometime]

Don't be so sure of that. There are many riders who'll disagree with you on this. I can feel it like night and day. The more technical you take your riding, the more you'll feel the stiffness.

 

But if you are willing to bet on 98%, how about a little wager? We'll need a demo fork that has QR/TA switchability, a nice rocky technical singletrack and 20 riders. Willing to bet your car/house that more than 98% CAN feel the diffs? (Bear in mind only 1 person needs to win the blind test and you lose).

 

The difference is night and day comparing what to what? Exactly the same fork, in exactly the same condition, running the same +ve and -ve air pressures just one had QR and the other TA? Oh and I assume exactly the same wheelset, with the same tyres also at the same pressure?

 

But you're right my bet is a little cheeky. It's probably 95% of Hubbers that won't tell the difference.

[nishiki]

The difference is night and day comparing what to what? Exactly the same fork, in exactly the same condition, running the same +ve and -ve air pressures just one had QR and the other TA? Oh and I assume exactly the same wheelset, with the same tyres also at the same pressure?

 

But you're right my bet is a little cheeky. It's probably 95% of Hubbers that won't tell the difference.

Yes, exactly the same bike, tyres, pressures, same piece of trail etc.

 

If you know what to feel for, you will feel the difference. If you haven't felt this difference, then you maybe don't ever ride in situations where having a stiffer front end would make a difference.

[Grebel]

A positive regarding Qr over TA is that they are cheaper to replace when thy are damaged. I just stripped the thread on my Boxxer 20mm TA and I'm looking at R650 to replace A QR would be leass than 20% of that (provided you don't wear spankex and weigh your shoes...) I wouldn't trust a QR for any trail type riding though (Depending on how big you huck of course!)

[sometime]

Yes, exactly the same bike, tyres, pressures, same piece of trail etc.

 

If you know what to feel for, you will feel the difference. If you haven't felt this difference, then you maybe don't ever ride in situations where having a stiffer front end would make a difference.

 

Huh? You didn't answer if the fork was exactly the same which is really what this topic is about? Which make and model of fork was QR and which was TA?

Edited October 19, 2012 by sometime

[GoLefty!!]

Quite observant. Yes, I purposefully didn't say anything about stiffness because I think it is nonsence. I'm very cynical about anything that is supposedly better through the mechanism of stiffness.

 

We dont feel huge twisting (as in turning the steering) forces through the handlebars when we ride a bike. This means that there is no such force. Hold your bike in the upright position with the saddle between your knees and the back wheel between your ankes. Have a friend twist the front wheel with a force that you expect would flex the hub/fork joint. Notice the huge force on your handlebars and tell yourself that you've never felt force like that when riding. So where does it come from? It doesn't exist.

 

Most of these "stiffer" arguments are all post-rationalised. Usually it is just a better design (TA, tapered head tube, hollowtech etc etc) than the original. It doesn't make for great brochure writing to just say, "New, Improved Design." The old one was crap but we tried again". It is far better marketing to say, better, lighter. stiffer, faster, hence the huge emphasis on stiff. The same ad agency that works for Pfizer's Viagra department, I suppose.

 

But back to the stiffness. Most of the flex is hubs was eliminated when front wheels became suspension-firendly. This was the increase in diameter of the hub's centre section. Just compare a 1990s MTB hub with today's. After than, I don't think the TA did anything new. If you analyse the TA, you'll notice that the axle (the part that screws into the fork) sits relatively loose inside the wheel with some play.To me this means that the axle simply provides clamping and the end cups on the wheel provide the support. Some of them are even made from plastic or thin alu. Not steel, not press-fit on the axle. Just a loose, easy affair.

 

Had we really required stiffness there the mechanism would have been far beefier as on DH bikes. Here the axle is usually pinch-bolted onto the fork at both ends or in the case of semi-QR models, screws in on the one side and press-fits on the non-screw side.

 

In summary, I believe we have adequate stiffness even in QR for the little forces the wheel experience. TA is better but for other reasons.

 

 

Exactly,

 

Stiffness is a function of overall design. Most of the QR15 forks have a stanchion 1mm bigger in diameter than the QR forks.

Tapered head tubes add some more stiffness but the one element that matters most is the wheel and forks crown.

 

The Cannondale Lefty gets all of this right through being a upside-down double clamp suspension with a massive diameter compared to conventional forks. The fact its a 20mm bolt on axle is really just a better fixing mechanism and allows for decent size bearings than can accommodate flex to the flange transferred from the rim via the spokes. Smaller bearing are more sensitive to the deformation of the bearing race under those loads.

 

One thing to watch out for with the double legged Thru_axle designs is that each brand has a different design. Shimano is QR15 with Fox, Manitou, DtSwiss, Marzocchi and Magura adopting the standard while SRAM is 20mm Thru-Axle. This creates problems when speccing a front hub

Edited October 19, 2012 by GoLefty!!

[Johan Bornman]

Viagra sells itself Johan It definitely makes things much stiffer, as with the TA.

 

I can feel the stiffness (of the TA fork vs QR). Makes perfect sense mechanically as to why as well. On one you have a 20mm bar threaded between 2 points and clamped, the other you don't. I'm sure we could find a fork that has both options and test this. Any takers?

 

You're confusing us here. Most of us are talking 15mmTA. In my post I mentioned 20mm and the differences.

 

A test on this is very, very easy. We stay away from the subjective "feel."

 

We take two exact forks and the same wheel, with a Hope hub. We clamp the fork in a jig and hang a weight from the wheel in two or three different positions. We measure the deflection. We clamp the idential QR fork in a jig, convert the wheel to QR and repeat the experiment.

 

I'll provide the deflection meter, jig and wheel. Someone needs to come up with the two forks and some beer.

 

The Yellow Saddle Laboratory awaits the white coats.

[GoLefty!!]

Just make sure its a significant weight, like 150Kg.

[lock]

You're confusing us here. Most of us are talking 15mmTA. In my post I mentioned 20mm and the differences.

 

A test on this is very, very easy. We stay away from the subjective "feel."

 

We take two exact forks and the same wheel, with a Hope hub. We clamp the fork in a jig and hang a weight from the wheel in two or three different positions. We measure the deflection. We clamp the idential QR fork in a jig, convert the wheel to QR and repeat the experiment.

 

I'll provide the deflection meter, jig and wheel. Someone needs to come up with the two forks and some beer.

 

The Yellow Saddle Laboratory awaits the white coats.

 

YES!!! this will give that number that everyone is looking for but Johan...I'll bet that 5% of all hubbers...will still disagree and tell you the TA is stiffer..

 

The most common excuse is that if you do not feel the difference..you're not riding hard enough....I think that correct spoke tension will make a far bigger noticeable difference...

 

having said that, I'll buy the one that is on special...

[LOOK695]

No stock of Rockshox Reba tapered steerer TA .

[rob7x]

Will a tapered steerer make a noticable difference in the same way a TA supposedly does/does not?

[GoLefty!!]

NO