Hetre 650x42 air pressure

[p nut]

What are you guys running your tire pressures at? My rides are usually 90% pavement, so tried ~50psi yesterday. Still felt a little squirmy, although felt great on rougher roads/dirt. This is my first foray into 650b and and "supple" wide GB tires, so maybe it's just something to get used to. I weigh around 155lbs by the way. Thanks for any input.

[Wilkinson4]

I am about 145-150 or so. I run mine anywhere between 55/48 to 48/36 depending on the surface. If pavement, I think 55/48 is good for me.

It will feel that way since the tires, especially the front will deflect much more that you are used to when out of the saddle. You'll get used to it and that is what makes them special over rough roads.

Play with the pressure. There was a calculator that recommended front/rear pressures based on the loading and tire drop but it resulted in really low front pressures and wasn't very practical.

Start here

http://janheine.wordpress.com/2010/10/18/science-and-bicycles-1-tires-and-pressure/

Then here

https://docs.google.com/spreadsheet/ccc?key=0AiAk2_n1YDEidFp6OWpxRHpGdGVXbHQzYy1pX3BMV Gc&hl=en#gid=0

Use the low trail column. Cell E2 is tire width, cell E3 is Bike+Rider weight.

mIKE

[p nut]

Thanks, Mike. I'll try those pressures and see how it does. I do think upping the front pressure will help. Thanks for the links as well.

[Wilkinson4]

Let us know what you end up with, could be a good reference. Some more good articles. Jan is now posting so he can certainly provide some real work experience since he has probably done more research on tire pressure, rolling resistance and flex than anyone around.

http://www.bccclub.org/documents/Tireinflation.pdf

http://www.bikequarterly.com/images/TireDrop.pdf

mIKE

[jamesutiopia]

They always feel squirmy, especially when new (those ridges might be to blame)

190lbs plus front bag, 55/65-70 lbs F/R. Can ride with less, but super low pressure adds a "bouncy" dimension that I prefer not to deal with wile cornering on high speed descents. I basically use the Berto chart to figure out the rear and put 85-90% of the rear pressure in the front.

YMMV

[lukasz]

165 lbs and I had them at around 35 psi for a camping trip yesterday. Try like 35 rear 32 front and get used to the cush, then go down to like 30/28. I was pushing them down some descents with my body weight and probably 30 lbs of stuff at 35/35 and was just then feeling the point at which the sidewall was starting to talk to me. I would never put them above 40 psi at my body weight. You're defeating the purpose of riding a fat tire.

[p nut]

I'll try a lower pressure as well, but not sure I'd go down to 30. Sounds like pinch flat city on the rougher roads? But I'll play around with the pressure as I get more rides in. Thanks for the inputs.

[plattyjo]

I typically like higher pressures on my tires, so I run my Hetres at 65 psi (and I weigh 135.)

But off-road, I dropped them down to half that (and was loaded with tons of camping gear) and had no problems with flats or handling.