Velocite Gram SL wheelset – a new contender for the pro peloton

Today marks the first step of the final stage of this new wheelset’s development. What is this step? Well, the first test prototype was delivered to us, and we sent it to our local 80kg+ UCI pro rider with a challenge to destroy them.

Velocite Gram SL prototype wheels
Velocite Gram SL prototype wheels

Background. Their development started almost 12 months ago when we asked GLM (Giant Light Metals) to make us 25mm carbon/alloy clincher rims since this would automatically grant us a UCI standard wheelset given our spoke lacing preferences (steel only, 20/24 minimum).

The brief seemed simple since the technology for making carbon reinforced alloy rims is not new and GLM after all has some major clients and technology at their disposal. Alas, the original samples that we received were anything but usable. The rims weighed 530g and 540g each! GLM and I both found this actually comical so they went back to the drawing board. The follow-up promise was 470g while meeting all the strength and stiffness requirements. This was getting closer to what we were expecting, and to GLM’s credit they did not rest there, they kept pushing themselves and their technology to make something extraordinary, something that would make us happy.

The final version samples were delivered two weeks ago, weighing 405g and 410g each. This weight is excellent and was achieved by careful re-engineering of the G609 alloy base, as well as by welding the rims, same as what we specified with the Tenax rims.

Gram SL intended end use is pro racing. Yes it is a clincher, but you will find many clinchers in pro races around the world and the 25mm profile is remarkably versatile and robust.

With the pro racing in mind we wanted to deliver a wheelset that can withstand the power outputs of top racers and satisfy the acceleration and handling requirements, without excuses. They also need to be serviceable in the field without requiring special tools, or unreasonable amounts of time.

Velocite Gram SL prototype front wheel
Velocite Gram SL prototype front wheel laced “elbows out” for maximum stiffness

The front wheel is laced with 20 spokes in the “elbows out” configuration to maximize the bracing angle, while the rear wheel uses 27 spokes (!) in a 2:1 pattern with 18 crossed spokes on the drive side and 9 radial spokes on non-drive side. To my knowledge this makes the Velocite Gram SL the only modern wheelset with a 27 spoke rear wheel. 18 crossed spokes on the drive side should mean absolutely amazing power transfer and “pick up”.

By using the 2:1 lacing we also achieved very good spoke tension ratios between drive-side and non-drive side. Non-drive side spokes are at 80% tension of the drive side, which is a lot better than the usual 50% tension with some 1:1 laced wheels. 2:1 lacing should extend the fatigue life on non-drive side spokes due to less variation in tension.

Velocite Gram SL prototype rear wheel
Velocite Gram SL prototype rear wheel with 27 spoke 2:1 lacing pattern

Spokes are Pillar PSR X-TRA 1422 aero blade spokes that distinguish themselves by being some of the least ductile spokes on the market, and by having very high ultimate tensile strength for their weight. Low ductility means that the wheels will remain true under extreme stress, and that they should be very stable over rough terrain.

To assist the spokes with their job of keeping the wheel true, we are using Alpina ABS locking alloy nipples. These alloy nipples use a special, patented nylon insert made by DuPont that locks the spoke in place, without seizing it. This means that building the wheel is straight forward and rebuilding it is not any different to rebuilding any other spoke and nipple wheelset.

Locking the spokes in place and using low ductility spokes means that the wheels should remain true until nipples, spokes, or hubs reach their fatigue failure point, a long time in the future. In theory.

This is why we are conducting this first live test with a pro rider, and why if they survive for at least a couple of weeks, we will order more samples and open the live testing to more volunteers. We need to make sure that our theory stands up in practice. Velocite Gram SL are intended to change the game, so the expectations of their performance are very high indeed.

The last thing is also one of the most important things. The weight. Gram SL prototypes built as above with our (Chosen) Velocite OS15 hubs with oversize axles and bearings is just 1382g actual. There is no rider weight limit, but our assumption is 110 kg max before premature failure is expected.

I will keep you updated on the live testing progress, which will hopefully start by proving our theories and design direction right…

  • Anonymous

    Hi Victor,
    I was wondering whether or not these new rims had straight pull spokes?

  • The rims can use any standard stainless steel spoke, straight pull or J-bend. The hubs that we use with Gram SL wheels use J-bend spokes.

  • Neil

    Good light spokes there, I’d never heard of Pillar before but those look on par with cx-rays!

    Any reports on how they’ve fared in the first week of testing? These look perfect for Scottish roads, light and quick to accelerate but strong enough to deal with questionable road surfaces.

    Any ideas on a price point for these wheels?

  • vmajor

    Pillar or Sha-Dar are a Taiwanese brand and are used a lot by many brands, but since they do not have a major brand name, these brands do not necessarily mention it. I am hopeful that the spokes will live up to their promise. We had variable success with DT Swiss. Sapim are nice, but we cannot use them due to limited availability – we still need to make our wheels and on paper at least Pillar spokes have superior mechanical properties for our needs.

    Price, not determined yet. When we finalize the build specifications we can start figuring out the price point.

    The initial test over some very rough surfaces has been positive. The wheels remained perfectly true as predicted. One more week of this and we will order some more test samples.

    BTW, we moved the blog to our own server and we are still working on it so I hope you find it in good repair when you visit it next 🙂

  • Neil Crawford

    I like the new blog page, very well put together!

    Pillar look excellent and lots of folk like them over on the WW forums, having a look over their website they do some really interesting products.  A set of wheels with white anodised spokes – bling bling ;-).

    Good to hear the wheels have done well so far, if you need additional testers let me know!

  • Thanks Neil 🙂 Yes I am hoping the Pillar spokes work out well. I am also looking forward to the day when we can start thinking of colour matching some more. White spokes though…I think you can only get them white by powder coating and that adds measurable weight. Ours are ED coated which is the basic, and effectively weightless coating. Other colours are possible using a different process.

  • Neil Crawford

    I saw these on their website, though to be honest I don’t know what a nanometer colourful coat is.  It looks like one of them is a white/pearl/silver finish.

  • NCC coating. Yes…it would be mostly white. We have been thinking of “tricking out” the wheels with few feature spokes. Will revisit that when Gram SL is ready for production.

  • guest

    Hi Victor, how is the testing going on these wheels?

  • …slowly. Had a problem with the front hub that we are resolving. Unfortunately this is the only set that we have so we cannot resume testing until we fix the issue. I ordered another 20 rims (10 sets) for wider testing. They should arrive in about 30-40 days and we’ll offer the wheels through our live testing program.