Rear Tire Pressure - General Altimax RT43

[jbs1218]

Those of you who are using the Altimax RT43 tire on the rear of the Spyder, what tire pressure are you running at? Thank you.

Jim

[Deanna777]

Those of you who are using the Altimax RT43 tire on the rear of the Spyder, what tire pressure are you running at? Thank you.

Jim

Jim
I am running the General Altimax RT43 tire on the rear of my spyder.

I am running 26PSI.

I ride solo.

Deanna

[Navydad]

19 psi

[safecracker]

I ride double most of the time and I have 20 lbs of air.

[ButterSmooth]

Take the tires max load and divide that by the max inflation pressure (all on the tires side wall). That will tell you how many pounds of load each psi of tire pressure will carry. Divide the weight actually on the rear tire (fully loaded with you gear and fuel) by that result and you'll have a good starting pressure. Set the tire (cold) to that pressure and go for a 'normal' (for you) ride. Check the pressure when you finish the ride. If the pressure doesn't increase the starting pressure is probably too high. If it increases more than 4 psi the starting pressure is probably too low.

I run my rear tire at 16 psi (not an Altimax) and after a good ride it goes up 2.2 psi., so I'm in the ballpark. It's handy to have a scale nearby.

[Peter Aawen]

with that! ButterS has laid it out very succinctly for you!

Anything over 20 psi is very likely too high, unless maybe you & your load weigh in over something like 600 lbs!! . But instead of repeating what's been put out there many many times already, I'd suggest that you simply type 'tire pressure' into the search field up the top right, tick the drop down box that says 'Search Titles Only' & hit the magnifying lens button, then settle in for some quality reading time! . Here's one I prepared earlier, that may or may not work for you...

https://www.spyderlovers.com/forums/...archid=3294433

Sure, the results you'll get back from that search may not ALL be about the Altimax RT43 Specifically, but it's mostly about car tires of the same size, same construction, and same sort of load range, so the pressures required are very similar, generally within +/- 2 psi, unless you & your load weighs A LOT, or a tiny amount, but give or take 300+ lbs or so, the recommended pressures of about 16-18 psi for an auto tire under the rear of a Spyder is within the 'of no further benifit & largely just time wasting for most to try to adjust more exactly' range.

Over to you jbs.

[jtoro1]

18 psi works good

[DGoebel]

I rode my '13 RTL with GA RT43 at 18lbs Solo, 20lbs if on extended 2 up rides. Tire lasted about 30,000 miles and I might've spun it or drifted it a couple times.

[canamjhb]

I'm a big ol' fat guy (over 250) + gear. I settled on 18 after trying lower and higher pressures. The Altimax preformed perfectly at that pressure..... Jim

[Bensonoid]

20 psi w/ 2 up.

[JayBros]

Twenty even.

[jbs1218]

with that! ButterS has laid it out very succinctly for you!

Anything over 20 psi is very likely too high, unless maybe you & your load weigh in over something like 600 lbs!! . But instead of repeating what's been put out there many many times already, I'd suggest that you simply type 'tire pressure' into the search field up the top right, tick the drop down box that says 'Search Titles Only' & hit the magnifying lens button, then settle in for some quality reading time! . Here's one I prepared earlier, that may or may not work for you...

https://www.spyderlovers.com/forums/...archid=3294433

Peter, thank you for info. I did the search as you suggested and found some good information.

[jbs1218]

Take the tires max load and divide that by the max inflation pressure (all on the tires side wall). That will tell you how many pounds of load each psi of tire pressure will carry. Divide the weight actually on the rear tire (fully loaded with you gear and fuel) by that result and you'll have a good starting pressure. Set the tire (cold) to that pressure and go for a 'normal' (for you) ride. Check the pressure when you finish the ride. If the pressure doesn't increase the starting pressure is probably too high. If it increases more than 4 psi the starting pressure is probably too low.

I run my rear tire at 16 psi (not an Altimax) and after a good ride it goes up 2.2 psi., so I'm in the ballpark. It's handy to have a scale nearby.

ButterSmooth, thank you. I need to get my calculator out.

[jbs1218]

Deana, thank you and I am curious as to why 26 lbs? It seems like most are running at approximately 18 psi.

[Grayfox]

18 in all three

[2dogs]

I'm running 17/18 cold and the center is wearing faster than the outside edges. Lots of rubber on edges, down to the wear bars in the middle.

[jbs1218]

2Dogs, how many miles do you have on your rear tire?

[Partzman23]

Mostly 2 up with the General Altimax RT43 at 18psi works good for me.

[Woodaddict]

General Altimax RT43, 18 or 19 solo or double

[2dogs]

2Dogs, how many miles do you have on your rear tire?

30k+ and the center is getting a little thin. I've got a new one sitting in the garage so this time I'm going to drop the PSI to 16 and see how that works. I run 16 in the front and there's hardly any signs of wear. Hot the rear gets to 20 and the fronts get to 18. I'm getting pretty good performance and wear but I think I can improve it just a little more.

[ButterSmooth]

30k+ and the center is getting a little thin. I've got a new one sitting in the garage so this time I'm going to drop the PSI to 16 and see how that works. I run 16 in the front and there's hardly any signs of wear. Hot the rear gets to 20 and the fronts get to 18. I'm getting pretty good performance and wear but I think I can improve it just a little more.

If you run the pressure formula on the front tires, you'll discover the fronts need more pressure than the rear. They have more weight on them and a lower load rating because of the smaller tire cross section. I've also discovered the fronts can 'tuck under' in an emergency maneuver (rock dodge in my case) if they're too soft. I'm at 19 psi in front and 16 in the back. But, I'm putting too fine a point on it.

[Peter Aawen]

30k+ and the center is getting a little thin. I've got a new one sitting in the garage so this time I'm going to drop the PSI to 16 and see how that works. I run 16 in the front and there's hardly any signs of wear. Hot the rear gets to 20 and the fronts get to 18. I'm getting pretty good performance and wear but I think I can improve it just a little more.

If you run the pressure formula on the front tires, you'll discover the fronts need more pressure than the rear. They have more weight on them and a lower load rating because of the smaller tire cross section. I've also discovered the fronts can 'tuck under' in an emergency maneuver (rock dodge in my case) if they're too soft. I'm at 19 psi in front and 16 in the back. But, I'm putting too fine a point on it.

You probably can improve that wear a little more 2dogs, but remember the General Altimax isn't really a 'High Performance' tire, it's more of an 'All Season Touring Tire' designed to provide good comfort with reasonably good wear levels and confident handling in all weather conditions, but it's NOT aimed at providing the bee's knees in terms of steering, cornering, high speed performance etc! So as ButterS noted, the fronts generally do need a touch more air than the rear, and if you go too low, you can reach a point of diminishing returns! Dropping your rear tire pressure a tad more to 16 psi in order to get a little better tire life should be doable, altho it juuust might come at the cost of losing a bit of outright performance capability under emergency or high speed manoeuvres.... but because they're the steer tires, dropping your fronts down to 16 psi is far more likely to degrade your steering performance - possibly more than you're prepared for/likely to expect!

So if you really want better 'performance', it might be smarter to look at replacing those current tires with an All Season Sport/Touring tire, there's some pretty reasonable versions out there in sizes that work pretty well - the Vredesteins easily come to mind - and you shouldn't lose too much in the way of tire life with them either!. . Or, if you really want much better Dry weather performance & don't care so much about achieving the ultimate in tire life, there's tires that'll do that out there too - Toyo's & Yokohama's come to mind - they're still pretty good in the wet, but they're really designed to excel in the dry, and can do so with only a marginal loss in tire life if you get your pressures right!!

[2dogs]

If you run the pressure formula on the front tires, you'll discover the fronts need more pressure than the rear. They have more weight on them and a lower load rating because of the smaller tire cross section. I've also discovered the fronts can 'tuck under' in an emergency maneuver (rock dodge in my case) if they're too soft. I'm at 19 psi in front and 16 in the back. But, I'm putting too fine a point on it.

Good info. My starting psi on the fronts is about 15.5. I have approx 5 miles of straight line blacktop before I hit the twisties and the temps by then are up to approx 17.5. The rear is about the same depending more on ambient temps and engine heat warming up the rear tire. I'm not an aggressive rider so from experience and info from this site, I think the same starting psi all the way around could be a very good plan to follow for both safety and longevity. That's why I picked 16 cold.

[ButterSmooth]

... I'm not an aggressive rider so from experience and info from this site, I think the same starting psi all the way around could be a very good plan to follow for both safety and longevity. That's why I picked 16 cold.

I was running 16-17 in my fronts, which seemed to work well for my also 'non aggressive' riding style. Then I had an experience that demonstrated there's not always a choice how hard you wrench on the bars. A mid-curve 6-8" rock (new in the last 20 minutes) made me abruptly change my line. When I pulled on the bars the bike responded, but the lurch of the tire giving way was disconcerting. I want the tire to be firm enough, if required for an emergency maneuver -- that's when I went up to 19 psi cold. That pressure was later confirmed by the calculation. One pressure for convenience may be a false economy.

[2dogs]

Did you miss the rock?