Rim-fork width probs with Zipp or Bontrager Aeolus D3 wheels?

[dragon76]

I'm considering getting a set of Zipp or Bontrager Aeolus D3 carbon tubies - these have rim widths in the neighborhood of 27mm. I took a look at my fork and existing wheels: rims are 20mm wide, and by eyeballing, I'd say there's about 5-8mm of space between the outsides of the rims and the insides of the fork legs (as well as between the rims sides and chainstays at their closest proximity). This is to say that my fork's legs are about 30-36mm apart (I don't have a proper pair of calipers to measure at the moment).

We all know about wheel flex, which is why we need to leave enough space between the brake pads to clear this movement, so I'm curious as to what people have found, from personal experience, when using rims that are around 27mm wide with forks and chainstays that only offer about 30-36mm, and if any rubbing occurs from the flex during hard efforts?

Thanks in advance.

 

[alienator]

I'm considering getting a set of Zipp or Bontrager Aeolus D3 carbon tubies - these have rim widths in the neighborhood of 27mm. I took a look at my fork and existing wheels: rims are 20mm wide, and by eyeballing, I'd say there's about 5-8mm of space between the outsides of the rims and the insides of the fork legs (as well as between the rims sides and chainstays at their closest proximity). This is to say that my fork's legs are about 30-36mm apart (I don't have a proper pair of calipers to measure at the moment). We all know about wheel flex, which is why we need to leave enough space between the brake pads to clear this movement, so I'm curious as to what people have found, from personal experience, when using rims that are around 27mm wide with forks and chainstays that only offer about 30-36mm, and if any rubbing occurs from the flex during hard efforts? Thanks in advance.

There are a few frames that have issues with some of the new, wide rims and/or wide aero rims. Cervelo's S3 had such such issues, but I'm not sure which other frames are having issues. Your best bet is to talk to the frame manufacturer and the wheel manufacturer. The conflict, if there is one, happens mostly with aero frames.

 

[dragon76]

That totally explains why the pro teams riding Cervelos went with Mavic - and I can only laugh now at the articles I've read where journalists were so surprised to see an aero bike company like Cervelo go with anything other than Zipp.

I checked out the current Zipp website and it looks like 303s are the main culprit at 28.5mm wide in some places of the rim. People like me riding Specialized frames (e.g. Tarmac) complain of rub with the Firecrest 303s during sprints. But I see that the 404s are slightly narrower overall at 27.07mm wide, and maybe these would JUST clear the fork legs and chainstays of a Tarmac/Venge. Anyone can confirm?

 

[alienator]

That totally explains why the pro teams riding Cervelos went with Mavic - and I can only laugh now at the articles I've read where journalists were so surprised to see an aero bike company like Cervelo go with anything other than Zipp. I checked out the current Zipp website and it looks like 303s are the main culprit at 28.5mm wide in some places of the rim. People like me riding Specialized frames (e.g. Tarmac) complain of rub with the Firecrest 303s during sprints. But I see that the 404s are slightly narrower overall at 27.07mm wide, and maybe these would JUST clear the fork legs and chainstays of a Tarmac/Venge. Anyone can confirm?

Actually it doesn't explain because the S5 doesn't really have an issue, and further the issue is Cervelo's not Zipp's. It's possible you might be able to avoid rub by having a wheel built that has different stiffness properties (both "loose" wheels and very "stiff" wheels can deflect a lot....but for different reasons). Also, there are other wide wheel makers to look at, namely Enve and 3T. Shimano's new aero wheels will be of the wide flavor, and I believe that Mavic's newest aero wheels, the ones only available to some pros right now, are also of the wide variety (The CRX80 is 28mm wide). With Enve, as well as Zipp, you can get the wheels built with the hubs of your choice. Why don't you call Specialized to find out what their thoughts are? You should note that both Omega-Pharma Quickstep and Saxo Bank are on Specialized bikes and Zipp wheels. Further, one thing that has to be kept in mind about "internet reports" from folks about their experiences is that......they should be taken with a grain of salt. They quite often come with very few details and a shortage of specificity. For instance, if someone gets "rub" on a Tarmac with 303's, are they sure it was the actual rim rubbing or was it the tire? If it's a tire, then it's possible to go to smaller cross section tire. Are they sure it was frame rub and not brake rub? What condition were their wheels in? Where they true and properly tensioned? How big was/is the rider? Is the rub regular or was it only occurring on that bumpy road?

 

[swampy1970]

Boonen is a big lad and he didn't seem to have much in the way of issues with his Specialized Roubaix frame and 303's fitted with 28mm FMB tubulars during his big day out... He also runs them at a whopping 60psi... Not sure why someone would opt for a 303 rather than a 404 unless they too were going on a cobble smashing escapade. Similar weight, not as aero but designed to give a bit more on crappy roads.

 

[alienator]

Boonen is a big lad and he didn't seem to have much in the way of issues with his Specialized Roubaix frame and 303's fitted with 28mm FMB tubulars during his big day out... He also runs them at a whopping 60psi... Not sure why someone would opt for a 303 rather than a 404 unless they too were going on a cobble smashing escapade. Similar weight, not as aero but designed to give a bit more on crappy roads.

I've heard Mr. Boonen can put out a hundred watts or two. The only reasons I can see for the 303's existence are the cobbles and its slightly better crosswind handling than the 404. Otherwise, given that you're paying the same as you would for a 404, I can't see not opting for a 404. I think the situation is the same with the Enve SES 3.4 vs the 6.7.

 

[Whale]

Originally Posted by alienator .

For instance, if someone gets "rub" on a Tarmac with 303's, are they sure it was the actual rim rubbing or was it the tire? If it's a tire, then it's possible to go to smaller cross section tire. Are they sure it was frame rub and not brake rub? What condition were their wheels in? Where they true and properly tensioned? How big was/is the rider? Is the rub regular or was it only occurring on that bumpy road?

alienator has some really good points here. Although rumors run rampant one of the very few instances of confirmed Pro-level frame rub was with the Zipp Sub9 and the early P3 models where the old standard disc had to be used. In our experience (multiple installs and customer feedback) 303 and 404 Firecrest wheels run fine on Specialized frames, including Tarmacs. If you have a really old Tarmac that was produced before the current wide rim trend I could see some potential for problems but wouldn't be able to confirm it easily. Some important information you might want to post to help us help you might be:

1. Exact frame model and year
2. Your weight
3. Planned tire width
4. Riding style

Also it's important to note that most wheel flex is centered 180 degrees from the ground. This is because the rim stays fairly stiff and the spokes are (doing their job) and flexing causing equal and opposite flex at the top of the rim. This is why most rubbing occurs at the brake (closer to opposite of ground contact). Also it's worth noting that fork and front brake rubbing is very rare considering how little of your weight is placed on the front wheel and that the cockpit is usually slightly angling with your sprint.

 

[Whale]

Originally Posted by alienator .


I think the situation is the same with the Enve SES 3.4 vs the 6.7.

I couldn't agree more. The 6.7s are butter. Crosswind handling is on par if not better than the 303s.

 

[dragon76]

1. Exact frame model and year: 2004 Specialized Allez Pro, 54cm. I'm looking to buy a Tarmac SL4 or Venge one day, so would like any wheels bought now to carry over.
2. Your weight: 153-160 lbs, depending on proximity to Christmas/Thanksgiving
3. Planned tire width: Whatever is recommended for the Aeolus 5 D3 or Zipp 404 FC tubies, probably Conti Comps and GP4000s (likely either 22mm or 23mm)
4. Riding style: Used to be more of a hard sprinter when I had more time to work on max power, go to the gym, etc., but now as a dad of two w inconsistent training, more of a steady effort guy who may still get back into sprinting form later on.

The point about wheel flex being mainly at the top of the rear wheel is a good one. This may mean that I'll be ok with 27mm wide wheels as there's plenty of clearance at the top rear right now, and the approx 36mm chainstay/fork width areas may not matter.

 

[alienator]

1. Exact frame model and year:  2004 Specialized Allez Pro, 54cm. I'm looking to buy a Tarmac SL4 or Venge one day, so would like any wheels bought now to carry over.
2. Your weight:  153-160 lbs, depending on proximity to Christmas/Thanksgiving
3. Planned tire width:  Whatever is recommended for the Aeolus 5 D3 or Zipp 404 FC tubies, probably Conti Comps and GP4000s (likely either 22mm or 23mm)
4. Riding style:  Used to be more of a hard sprinter when I had more time to work on max power, go to the gym, etc., but now as a dad of two w inconsistent training, more of a steady effort guy who may still get back into sprinting form later on.

The point about wheel flex being mainly at the top of the rear wheel is a good one. This may mean that I'll be ok with 27mm wide wheels as there's plenty of clearance at the top rear right now, and the approx 36mm chainstay/fork width areas may not matter.

The Enve SES 6.7 is 24mm wide in the rear and 26mm wide on the front. The Enve SES 3.4 has the same width specs. The Zipp 404 is 26.53mm wide while the 303 is 28.5mm wide. I think you'll be unlikely to have a problem with any of them, especially the 6.7 or the 404.

 

[Whale]

+1 for alienator

 

[swampy1970]

Originally Posted by dragon76 .

1. Exact frame model and year: 2004 Specialized Allez Pro, 54cm. I'm looking to buy a Tarmac SL4 or Venge one day, so would like any wheels bought now to carry over.
2. Your weight: 153-160 lbs, depending on proximity to Christmas/Thanksgiving
3. Planned tire width: Whatever is recommended for the Aeolus 5 D3 or Zipp 404 FC tubies, probably Conti Comps and GP4000s (likely either 22mm or 23mm)
4. Riding style: Used to be more of a hard sprinter when I had more time to work on max power, go to the gym, etc., but now as a dad of two w inconsistent training, more of a steady effort guy who may still get back into sprinting form later on.

The point about wheel flex being mainly at the top of the rear wheel is a good one. This may mean that I'll be ok with 27mm wide wheels as there's plenty of clearance at the top rear right now, and the approx 36mm chainstay/fork width areas may not matter.

If you really put out 100 megawatts during a sprint then make like Cav and have the rear wheels built with a few extra spokes otherwise consider working on your form during a sprint. Research by Mavic suggests that a really stiff rear wheel is worth about 100 watts in a sprint.

A 2004 frame was never designed for wheels as wide as the current generation of Zipps. The SL4 and Venge are...

 

[dragon76]

I took a look at the 2012 Venge, and by eyeball and by my "try to stick a pinky between the rim and the fork leg or chainstay" test, there's actually about the same amount of clearance as with my 2004 bike. It's still around a 8mm gap. Even older frames had to account for riders who want to use wider tires (25mm, 28mm, etc.) regardless or rim widths at the time, I suppose.

I went a bought a cheap pair of calipers and finally got to measuring the spacing on my frame, and it's 36mm between the fork legs at the closest, and same with the chainstays. So, with 36mm - 27mm (rim width) = 9mm, there's 4.5mm between rim side and fork leg/stay, which as a Zipp rep told me is fine (needs to be a min 3mm).

I can now get either Zipp 404 FC or Aeolus 5 D3 with no probs.

Cheers!

 

[alienator]

If you really put out 100 megawatts during a sprint then make like Cav and have the rear wheels built with a few extra spokes otherwise consider working on your form during a sprint. Research by Mavic suggests that a really stiff rear wheel is worth about 100 watts in a sprint.

Where's the Mavic reference for that?