Disappointing PT Wheel Build

Hmmm.....are you training to race or what??? It may feel slow by a sec or 2??? I doubt that the laggy feeling would distort your power number at all.

Russ968 said:

I'm in my first 2 weeks of data gathering with my new PT SL and have found myself a little disappointed in the wheel I had built up. I had a 28 hole PT SL laced to a DT Swiss RR 1.1 hoop with CX-Ray spokes by a reputable wheel builder. 2X lacing on both sides. Mavic Ksyrium SLs and Bontrager Race-X-Lites have been my wheels for the past year, both fairly stiff machine made wheels with low spoke count/high spoke tension designs. I liked them both.

My issue with the new wheel is slow acceleration from what I perceive to be a noticeable "wind up" when applying power particularly when sprinting and climbing. Once the wheel is up-to-speed it performs fine.

I've had it suggested to me, by someone I respect, that my options are few and this is the nature of "hand-built" wheels. Being a fairly new cyclist I thought I'd see if you had any suggestions or concur with this view. I'm open to virtually all options including having a new wheel built but short of switching to an Ergomo or SRM. I also am considering using this as a training wheel and perhaps building up a racing wheel set so I don't want to be in this situation again.

Thanks,
--Russ

You could have the wheelbuilder (or if you own a tensionmeter) you could see if the spokes can support a higher tension then the original build.

Erik

Isn't the left flange on PT hubs the driving flange? I would do 3X on both sides and make sure the tension is high enough.

Russ968 said:

I'm in my first 2 weeks of data gathering with my new PT SL and have found myself a little disappointed in the wheel I had built up. I had a 28 hole PT SL laced to a DT Swiss RR 1.1 hoop with CX-Ray spokes by a reputable wheel builder. 2X lacing on both sides. Mavic Ksyrium SLs and Bontrager Race-X-Lites have been my wheels for the past year, both fairly stiff machine made wheels with low spoke count/high spoke tension designs. I liked them both.

My issue with the new wheel is slow acceleration from what I perceive to be a noticeable "wind up" when applying power particularly when sprinting and climbing. Once the wheel is up-to-speed it performs fine.

I've had it suggested to me, by someone I respect, that my options are few and this is the nature of "hand-built" wheels. Being a fairly new cyclist I thought I'd see if you had any suggestions or concur with this view. I'm open to virtually all options including having a new wheel built but short of switching to an Ergomo or SRM. I also am considering using this as a training wheel and perhaps building up a racing wheel set so I don't want to be in this situation again.

Thanks,
--Russ

BlueJersey said:

Hmmm.....are you training to race or what???.

Yes.

BlueJersey said:

It may feel slow by a sec or 2??? I doubt that the laggy feeling would distort your power number at all.

You're right I don't think the power numbers are distorted.

I'd say something's wrong w/ your build - I had the exact same set-up and it performed flawlessly (until the eyelets started pulling out of the rim after 5000miles, but that's a problem with the RR 1.1.) I'd have your guy check the tension.

Russ968 said:

I've had it suggested to me, by someone I respect, that my options are few and this is the nature of "hand-built" wheels. Being a fairly new cyclist I thought I'd see if you had any suggestions or concur with this view. I'm open to virtually all options including having a new wheel built but short of switching to an Ergomo or SRM. I also am considering using this as a training wheel and perhaps building up a racing wheel set so I don't want to be in this situation again.

Thanks,
--Russ

I don't mean any dispect to those who made this observation, but I have to say that's one of the dumbest things I've ever heard. There's nothing inherently 'stiffer' about a machine built wheel.

The stiffness of the wheel is determined by amount and evenness of spoke tension, and the components used. My experience is that the components used in your build should result in a pretty stout wheel, so I wonder if the tension is too low?

Also, rim depth definitely contributs to the 'feel' of stiffness, so a deeper rim (say Velocity Deep V) would probably built up a stiffer wheel if you're dissatisfied w/your current set-up.

Lastly, I'd be pretty hesitant to base equipment decision based on 'feel', as it can be a pretty tricky thing. For instance, IIRC, the Ksyriums when tested by tour magazine really weren't that stiff--at least the rear. Just as really high tire pressure may 'feel' faster, as long as the wheel isn't rubbing the brakes or any of the frame members, I doubt that wheel stiffness would make a measureable difference in performance. Wheel aerodynamics, on the other hand.......

Thanks for the suggestions. I'd planned on getting back to the wheelbuilder and have the spoke tension checked...I'll also talk with him about the 3x rebuild.

Be careful about upping the spoke tension on a PT wheel. The hub has a thick flange which causes a definite bend particularly when you starting going towards 3x on a aero rim. If you can, invest in some Sapim 15/16 DBs and go 2x, the spoke will remain thin enough that the j-bend won't be effect 'too' much and you can crank down the tension.

RipVanCommittee said:

The stiffness of the wheel is determined by amount and evenness of spoke tension

Absolutely not. Unless the wheel is being torqued so hard that some of the spokes are going slack, the stiffness is not dependent on spoke tension. Increasing the spoke tension will change nothing aside from shortening the life span of the rim.