For those interested in rim inserts for gravel or mtb, I stumbled on these super light inserts: https://tubolight.bike
Just 29 grams per rim for the gravel/CX version. I have some on order and will chime back in with install experience etc.
For those interested in rim inserts for gravel or mtb, I stumbled on these super light inserts: https://tubolight.bike
Just 29 grams per rim for the gravel/CX version. I have some on order and will chime back in with install experience etc.
Would love to see how this alters rolling resistance.
Pardon the ignorance but why would this be useful for CX or gravel?
I thought these existed specifically for downhill gravity racing where the only option during a run can be to ride out a flat. They offer enough protection to help prevent catastrophic rim failure and help keep the tire seated in the rim which is important when you are hurling through trees at top speed. I don’t see how this translate to a CX race or gravel ride. For CX I would think tubulars provide a better solution to the same problem. For gravel I think you are going to be stuck fixing the flat no matter what and the the insert is only going to make this harder.
Pardon the ignorance but why would this be useful for CX or gravel?
I thought these existed specifically for downhill gravity racing where the only option during a run can be to ride out a flat. They offer enough protection to help prevent catastrophic rim failure and help keep the tire seated in the rim which is important when you are hurling through trees at top speed. I don’t see how this translate to a CX race or gravel ride. For CX I would think tubulars provide a better solution to the same problem. For gravel I think you are going to be stuck fixing the flat no matter what and the the insert is only going to make this harder.
They let you run lower pressures.
For those interested in rim inserts for gravel or mtb, I stumbled on these super light inserts: https://tubolight.bike
Just 29 grams per rim for the gravel/CX version. I have some on order and will chime back in with install experience etc.
Would love to see how this alters rolling resistance.
Very little, or not at all, if it’s not in contact with the tire. I’m not familiar with these but just going by the pictures, it looks like they’re intended to leave an air gap between themselves and the tire under normal circumstances. Presumably only being compressed when hitting a hard edge or when the tire losses pressure. On second glance, maybe the Tubolight is close enough to be compressed when running modest pressures which would increase rolling resistance, but the Evo version leaves lots of clearance.
I believe Dylan Johnson rode these to a top 5 finish at Belgian Waffle.
They let you run lower pressures which, in my experience, reduces your rolling resistance off road. They also provide rim protection and can offer sidewall support. It’s not explicitly stated as a benefit but I would hazard to say it would be near-impossible to accidentally roll a tire off a rim (if you had a flat going into a turn for example).
On road for all practical purposes the surface is incompressible so it’s not really a factor in CRR. Off road the earth beneath you does indeed compress so not only do you get hysteresis losses in the tire but in the road surface itself. Generally speaking, the wider the contact path the less the earth compresses and the lower the losses.
Where I ride my mountain bike we have lots of sand and loam. There’s a noticeable difference in rolling resistance between a 2.3†tire at the correct pressure and an identical 2.6†tire at the correct pressure (Vitoria Mezcals in both cases). I’ve fiddled with it with a power meter doing a relatively flat circuit with no brakes (so lots of coasting into turns) and the AP difference is in the 10-15w range by my reckoning. Dropping the pressure further on the 2.6†tire confers even more of a benefit over soft surfaces but at the expense of squirm and the risk of a rim strike. An insert helps mitigate both of these.
If you were to look at crr on the road with an insert the impact would probably depend on sidewall contact. Minimal sidewall contact relatively close to the bead should have a minimal impact on crr. The further down the rim and more extensive the sidewall contact the greater the crr penalty.
My $0.02, they are worth experimenting with if you ride off road.
Do you know where they shipped from?
Interested in the review, thanks in advance
I actually have pinch flatted a tubeless gravel tire hitting a rock going way too fast for the terrain. Damaged the rim and put a hole in the tire right by the bead. This would have prevented that. The idea is that it prevents you from flatting in the first place.
Also EF was experimenting with something like these during the tour, running tubeless with an insert that supposedly made them just as good as tubulars at not rolling off the rim after a flat. Super curious if these are related to that.
I understand the principle but it’s like buying the most expensive race tubulars on the market and then gluing on gator skins for flat protection.
The best schematic of how these things work I have found is here: https://hucknorris.com/ where it talks about preventing tire damage. To function properly these inserts must make the tire more rigid and be substantially wider than the rim. They also add a decent amount of weight to the system. For downhill and enduro I get it. For gravel if I’m racing I take the risk without them if I’m training I just ride tires and wheels that don’t require the insert.
I understand the principle but it’s like buying the most expensive race tubulars on the market and then gluing on gator skins for flat protection.
The best schematic of how these things work I have found is here: https://hucknorris.com/ where it talks about preventing tire damage. To function properly these inserts must make the tire more rigid and be substantially wider than the rim. They also add a decent amount of weight to the system. For downhill and enduro I get it. For gravel if I’m racing I take the risk without them if I’m training I just ride tires and wheels that don’t require the insert.
60grams is a “decent amount†of weight?
Why must they make the tire more rigid or be substantially wider?
What they might do (someone else can verify) is increase the spring rate of the tire by reducing the air volume. That increased spring rate allows lower pressures to be run.
The height of the insert above the sidewall gives the pinch protection, they don’t need to be wider than the rim to do that
I have no experience with the product that started this thread but I know how Cush Core and Huck Norris work. Both of those companies have really good diagrams on their website that show why and how these work. The height above the rim has very little to do the puncture protection. In fact adding height but not width would be a major problem in terms of tire stability. Because you are running at lower pressure you need lots of width too support the side wires and prevent burping/wiggling.
If you look at Huck Norris you will see it’s super thin but wide. Cush core uses a lower density foam so it’s taller but reaches the same width. And these products are 250-300g a pair. So the question is what happens when you reduce the weight to 60g? I don’t know but the product is making the same claims the big boys are so I assume the physics are the same.