when you lot say that any tyre under 800grams just wont cut it - what do you mean
you destroy tyres?
lots of flats?
have to run more air to stop them rolling on the rim?
destroy rims?
All of the above
Weight doesn't seem to make a difference to reliability, but I am not using 600g tyres for anything other than some XC and rail trails. Only had a single flat in the last 6 years, which was a bit of a doozy as it happened at the worst possible time and I will never run a snake skin rock razor again.
Mostly its about tyre squirm / rolling on the rim vs how much pressure needed to stop this. Tyres with a heavier carcass can run less pressure whilst still being stable. As a bonus heavier carcasses also absorbed more energy from the impact and less likely to ding a rim - so you can run less pressure without greater risk. I've only ever burped light weight tyres, regardless of how much pressure (28-30psi).
Nothing worse than having to run excess pressure and having the bike ping pong off every obstacle on the trail. I use a digital pressure gauge before each ride (it's a scientist thing, I guess), and 2-4 psi above normal makes a noticeable difference to ride quality.
Interestingly, with Maxxis Exo casings, it doesn't feel like its the same across there range, comparing a 600g exo ardent to a 950g 2.5WT DHF exo, the ardents side walls feel really flimsy in comparison, I don't think its just the larger knobs that add weight.
For instance comparing the same tyre in 3 carcasses (puhsys maxxis sale),
Maxxis SS
EXO 2.3 (750ish?) needs minimum of >26 psi an still feels squirmy if pushing, harsh chattery ride, not using mine anymore.
DD 2.3 (975) needs 22-23 psi, some squirm, but tolerable, when pushed hard in corners or sideways landing, smooth ride.
DH 2.5 (1330g) 21 psi, awesome tyre, very stable, Rolls well, but still shithouse to pedal its mass.
Really depends what your goal is, mines to have fun descending or jumping, running heavier tyres means I can run lower pressures and maximise traction, but I don't care how long the ascent takes, or even if I walk it now and then.
110kg, 29mm internal rims.
When I use a set of 471's (25mm internal) the pressures go up by about 4-5 psi at each end.
When I use some Mavic 521's, the pressure goes up 10-12 psi from 29mm internal.
As the rims get narrower, pressure goes up, tyre volume decreases, you get more squirm (at lower pressures), more dings, a harsher ride, started using Mavic D321's (29mm internal) in 1998, got on the wider rim crazy before it was cool and never looked back.
