Hi All,
I ride in and around London, on flat and hills. Average rider, weight 80kg for 177cm. I have recently bought the new wheelset bora wto 45.
Internal rim width: 19mm
External rim width: 26mm
Thinking of going tubeless with the Conti GP 5000, but unsure about tyre width. Could you please help me understand which one would work better?
Option 1) conti gp 5000 tubeless 25mm
It’d stretch out to roughly 26-27mm and be pretty much in line, if not slightly larger, than the external rim width (26mm). Better for aero, not as comfortable as 28mm.
Option 2) conti gp 5000 tubeless 28mm
It’d stretch out to roughly 29-30mm, much larger than the external rim width (26mm), so Not good for aero. However, better comfort than the 25mm, lower pressure, Potentially lower rolling resistance.
Also thinking of using Stan’s notubes sealant or orange endurance seal (45ml per tyre).
What do you recommend? Any experience with wheel/tyre?
Thanks so much,
I have the WTO 60s and run 25mm GP5000 TLs
They are brilliant tyres but I have three concerns with them.
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I’m worried that after a while they stretch past the external rim width so aero could be compromised.
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They are a pain but not impossible to fit first time - better if you warm them up first. Set aside 45-60 mins!
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They have a habit of fraying random strings from the side wall (google it - its a thing) they seem harmless - I just cut them off!
Even with these flaws I haven’t found anything better. Keen to try the pirelli p zero race tlr sl tyre in a 24mm but I’m struggling to find any in the UK.
In terms of sealant I use orange seal endurance but havent had any punctures that I’ve noticed having run the 5000s for a few years now.
If I was you I would rule out the 28mm for the front tyre but maybe stick one on the back if you want the extra comfort.
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Thanks Kev! It’s always great to hear from other fellow road cyclists and what their experiences are. Thanks for sharing.
I’ve heard so many mixed reviews - many people advocate the use of 28mm tyres for the extra comfort, others prefer the 25mm for the aero. Seems like the 25 are stretching out to 26-27mm anyway, so the added comfort would be there if I’m not wrong…
I currently have conti gp 5000 clinchers 28mm on a different set of wheels, and they are still great, so I might just take them down to 25 for when I mount the new wheelset later this week.
If anyone else has any other opinions/experiences, that’d be great
Oh, any advice on how to warm them up and fit them first time? Do you use warm soapy water, what tips and tricks do you have for me? 
Unpopular take time - (especially when given to a Campy rider, - I myself am a Campy rider…)
You describe yourself as an “average rider”, flats and low hills around London. The absolutely minuscule gain in aero benefits from a smaller tire (more closely matching your wheel profile) is not remotely worth the trade off in comfort and safety from the larger profile tire. the additional volume the 28s give you will better protect the rim, allow some “squeeze” room for the tubeless seal endurance, and give your backside some respite from that stellar tarmac around the London area.
The aero gain will be virtually undetectable, however you will feel the benefits of the increased volume on each and every ride.
My .02.
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Currently riding Bora WTO 60s with GP5000 TL 25mm tyres.
Few observations;
- The 25mm GP5000 TL appears to be perfectly inline with the width of the rim when inflated so doesnt conform to the 105% rule
- The GP5000 TL feel like a robust tyre and they are not very supple on rough surfaces
- For my A Event I am likely to move to a much more flexible 23mm or 24mm tyre to get the aero and comfort benefit
Hi Dave,
The reason why I’m considering the 25mm is that I’ve ought a wheelset that is aero, so fitting a tyre that is not aero doesn’t sound like the greatest idea. Average speed is 30-40kmh normally, I weigh 80kg (system weight is around 90kg including bike), and I see lots of people mounting the 25mm for the aero benefit, so not sure what to get… considering the hassle to set up tubeless, I’d like to choose the right tyre width first time instead of changing and experimenting tyres several times.
I really like and appreciate your point of view on the 28mm, as I currently have conti 28mm clincher (on a completely different and cheap wheelset) and can see the benefit vs the 25mm