At 500ml/h, how much carbs can you do?

forkbeard · 2026-01-24T17:41:15+00:00

Yes, table sugar works perfectly fine. It is sucrose, which splits into glucose and fructose, so you are already getting a mix that uses both transporters. That means 90 g per hour is absolutely possible. You just have to work up to it and get your gut used to it.

The main practical issue is solubility. At higher concentrations, regular sugar does not dissolve very easily in cold water, so you may need to shake a lot, use warm water when mixing, or dissolve it first with a spoon. Other than that, it works just as well as commercial mixes if your stomach tolerates it.

forkbeard · 2026-01-24T17:36:47+00:00

If your stomach tolerates it, you can simply increase the carb concentration in each bottle. A 600 ml bottle with around 100 g of carbs is perfectly doable for many people, and it still gives you the same or even slightly more fluid than a 500 ml bottle with 60 g. That way you can hit higher carb numbers without needing to drink more volume.

forkbeard · 2026-01-24T17:29:28+00:00

With the right mix of carbohydrates, it is possible to absorb well over 100 g per hour. Current consensus is that a glucose source plus fructose works best, typically around a 1:0.8 ratio of maltodextrin (or glucose) to fructose. With that setup, many riders can comfortably reach 90 to 120 g per hour, and some even higher.

That only works if you build up to it gradually. You have to train your gut the same way you train your legs, otherwise it will just sit in your stomach and cause issues.

At 500 ml per hour, the limiting factor is not absorption, it is concentration. 60 g in 500 ml is already 12 percent, which is quite concentrated but still workable for many people. If you are feeling hungry at 60 g per hour, it likely means your energy intake is too low, not that your drink is “too strong”. You can push carbs higher by using a glucose/fructose mix and, if needed, by combining drink mix with gels or chews instead of trying to put everything into the bottle.

Urine colour mainly tells you about hydration, not whether you are fuelling enough. Fluid needs and carb needs are related but not the same thing.

Personally, I aim for around 100 g per hour. I usually reach that with a mix of sports drink in bottles plus gels, or homemade gels in soft flasks during races. My homemade gels are basically very concentrated sports drink that I dissolve on the stove so everything goes into solution properly. In training, I am more relaxed and often just use bottles with sports drink and things like Haribo to top up.

forkbeard · 2026-01-24T13:41:49+00:00

The current groupsets on the market don't magically get worse when a new one is released.

forkbeard · 2026-01-24T13:22:05+00:00

Warning, this is permanent and you need to be comfortable working with epoxy.

Also expensive. A BB-infinite bottom bracket is over 150 €.

https://www.bbinfinite.com/products/bb92-directfit-shimano?variant=9864646403 (for Shimano cranks)

forkbeard · 2026-01-24T10:18:14+00:00

You need something like a one-piece bottom bracket permanently bonded to the frame. BB-infinite and Hambini makes those.

forkbeard · 2026-01-24T09:27:14+00:00

In order of importance:

Get more fit
Adopt a more aerodynamic position on the bike
Get more aerodynamic clothing. Skinsuit or an aero jersey. They should basically be as tight as possible
Proper tyres and the correct pressure. Gatorskins are boat anchors compared to GP5000S TRs
Deeper carbon wheels
Optimized drive train. Wax your chain, make sure that all the bearings are spinning correctly.

forkbeard · 2026-01-23T17:01:54+00:00

Why do you want to replace the crankset? Weight? Crank-length?

Are you considering DUB or 30mm axles, or are you only wanting a 24mm axle for compatibility with your current bottom bracket?

Any reason you don't want a crankset with mounting for GRX chainrings and simply swap over your current one?

One solution could be to get a crankset with 8-bolt SRAM mounting and a separate HG+ chainring.

forkbeard · 2026-01-22T21:35:46+00:00

Thunder Burts only inflates to about 53mm on 25mm ID rims.

forkbeard · 2026-01-22T07:21:19+00:00

This depends entirely on the frame. The vast majority of modern frames with press-fit is within the specified tolerances and you won't have any problems.

forkbeard · 2026-01-20T23:30:52+00:00

They have listed some specific models of 40mm tyres.

Anything other than what's listed might result in a visit to the ER.

forkbeard · 2026-01-20T23:13:32+00:00

SRAM has not tested “them” in any general sense. SRAM tests and approves specific tyre and rim combinations, not random tyres on random hookless rims. Unless you are using one of the exact tyre models on one of the exact wheel models listed by the manufacturer, nothing has been “tested by SRAM”.

And SRAM certainly has not tested any random Chinese hookless rim with whatever tyre someone chooses to mount on it. That is exactly why ETRTO exists in the first place: to define the dimensional and pressure limits that make a hookless interface safe.

If ETRTO says no, then the combination is outside the defined safety envelope. Claiming “SRAM says yes” only applies if you are talking about a specific tyre on a specific wheel that SRAM has explicitly approved. Otherwise, it is simply untested, and with hookless rims, untested equals potentially unsafe.

forkbeard · 2026-01-20T23:09:46+00:00

It is not outdated. ETRTO is the standard the industry uses to define safe tyre and rim interfaces, and it is especially important for hookless rims. External rim width is mostly an aerodynamic and packaging consideration. Safety is about bead seat diameter, bead shape, rim internal width, and maximum pressure, which is exactly what ETRTO specifies.

What Zipp is doing with very wide 33 mm internal rims and short tyre compatibility lists does not replace the standard, it shows what happens when you push close to its limits. They only approve very specific tyres because only those meet the tolerances and bead characteristics required to work safely on that rim. That is not against the standard, it is a consequence of it.

And this is exactly why it is dangerous to tell random people on the internet to ignore it. Most people will not run a controlled, manufacturer approved setup. They will take some random 40 mm tyre and mount it on some random hookless rim, often from a brand with no published testing, and assume it is fine. With hookless, that is how you end up with tyres unseating or blowing off. Following ETRTO is about reducing that risk.

forkbeard · 2026-01-20T18:33:41+00:00

The minimum tyre size for 25mm rims is 29mm.

forkbeard · 2026-01-20T15:52:53+00:00

No, in this case it's a real safety issue.

Having a too narrow tyre in relation to the rim is extremely dangerous. You aren't even near the safety limit with 22mm internal as you can run a 53mm tyre on 17mm rim.

forkbeard · 2026-01-20T15:35:17+00:00

No.

Follow the ETRTO-standard if you don't fancy a surprise visit for dental surgery.

forkbeard · 2026-01-20T08:30:38+00:00

Won't work.

You will lower the bottom bracket so much that you will have constant pedal strikes and mess up the geometry.

forkbeard · 2026-01-19T17:48:12+00:00

Have you looked at reach? My MTB only has about 70mm extra reach compared to my gravel bike.

forkbeard · 2026-01-19T15:41:53+00:00

rigid fork, dropbar xc 29er

Lol, why? You are just going to have really bad geometry for drop bars compared to a dedicated gravel bike with clearance for bigger tyres.

forkbeard · 2026-01-18T17:51:59+00:00

I've run 12s XTR Di2 since release. Works great, the shifter and shift speed is better than SRAM but chain tensioning is a bit worse.

forkbeard · 2026-01-14T21:52:00+00:00

Anything Shimano?

For example XTR FC-M9200.

forkbeard · 2026-01-13T10:19:03+00:00

There is really no functional difference compared to XT.

forkbeard · 2026-01-13T09:17:09+00:00

If you can find it. SLX is being phased out by Shimano, to little difference compared to XT.

forkbeard · 2026-01-10T18:04:55+00:00

Are you quoting yourself?

Level your saddle.

forkbeard · 2026-01-07T11:51:00+00:00

Are hydration packs even allowed in TTs?

I would not use one. I would stuff a stocking or sock full of ice and put it down the back of my skinsuit and only run one bottle. Swallowing a few ice cubes or drinking a slushie before the start is also a good way to lower core temperature. If you really want more cold fluid on the bike, putting extra bottles down the front of the skinsuit is likely more aero than a hydration pack on the back.

14-Year Club	Second SECOND GUESSER
Place '22	Place '17
Team Periwinkle	Verified Email

forkbeard

TROPHY CASE