AK550 Tire Pressure ?

[Luckyword]

Helpful discussion.

I had been running cold, 34fr and 38 rear.

Today I drove about 33 miles in 100 degree weather, and at the end of the ride, the onboard tire pressure gauge indicated roughly 46 front and 47 rear.

I'm thinking that when I'm going to ride in 100 degree weather, I'll lower pressure to around 30fr and 34 rear.

Should I run even lower when in 100 degree temps? Any thoughts?

[rjs987]

Helpful discussion.

I had been running cold, 34fr and 38 rear.

Today I drove about 33 miles in 100 degree weather, and at the end of the ride, the onboard tire pressure gauge indicated roughly 46 front and 47 rear.

I'm thinking that when I'm going to ride in 100 degree weather, I'll lower pressure to around 30fr and 34 rear.

Should I run even lower when in 100 degree temps? Any thoughts?

If you did NOT see the TPMS warning come on then no, I would not lower the psi. You set tire pressure based on when the tires are not yet warmed up from rolling on the road... IOW cold psi. That doesn't mean cold as in cold feeling to you but cold before the ride warms them up. So if you set the psi where you would normally set it and the ambient air temp is 100F then that is right for that air temp. If you set the very same psi when the ambient air temp is 70, or even 60, or less, then that is the right psi for that air temp even if the tire psi is set to the very same psi as at the warmer temp. Don't look to the hot psi to base what you set the tires to for the proper cold psi. The tires are designed to handle the warm up from riding on them and that is entirely normal.

IF the TPMS warning does come on in very very hot ambient air temps. ONLY THEN would be appropriate to use a SLIGHTLY lower the cold psi before you start riding. If you really feel you must lower the psi with the tires thoroughly warmed up then only drop the pressure 1 or 2 psi at most and then re-inflate to the proper psi when tires are "cold" before the next ride.

I've seen as high as 49 psi on the rear during riding in very hot air temps with no warnings so nothing should be done to lower the pressure.

BTW- If you ride somewhere on a very hot day and run into a store and then come back out to the bike to continue riding and the TPMS gives a warning when you first start up the bike DON'T worry about that. Ride a mile first before doing anything. More than likely, in that case, the warning will go away. It is just the TPMS system sensing the warmed up pressure in the tire but the TPMS sensor has cooled from not rolling... or maybe all the heat has migrated to the top of the tire and that happens to be where the sensor is located when you parked. I've seen that once or twice and after riding a half mile the warning is gone as the temp has equalized throughout the tire and on the sensor.

[Neil955i]

Really thorough answer there Bob and interesting, thanks!

[Kahuna_550]

Holy crap, good thing I red this post. I've been keeping both tires at 32. Been about 1600 miles so far 🤣🤦

[rjs987]

Holy crap, good thing I red this post. I've been keeping both tires at 32. Been about 1600 miles so far 🤣🤦

Even the owner manual says more than that! The owner manual says at least 34 front/38 rear psi. I prefer just a few psi higher for better performance and tire life. At least that's been my experience doing that. Low psi like you stated will wear out those tires rather fast.

I have really good grip in rain and on dry pavement with the pressures I stated earlier. And sometimes I do take curvy roads just a little aggressively (from my days riding with the sport touring group on my ST1100) but mostly I ride conservatively speed-wise. I just replace my front tire at 6670 miles. I consider that pretty fair. I know a lot of sport touring riders who get about the same and one or two who get half that (they are really aggressively fast in curves). It's just slightly more miles than my Burgman 650 was and also my CTX1300 depending on tire brand/model. Though I find it interesting that most of the riders I ride with wear out the rear tire long before the front. I still have several thousand miles to go on the rear tire of my AK.

[randyo]

I haven't checked my pressure, till today, I got my new Autometer tire gauge , need to put a couple psi, AAAACK! my chuck won't fit between the wheel and brake rotors to get on the valve stem........ a short right angle chuck is on order, be here Saturday

[rjs987]

I haven't checked my pressure, till today, I got my new Autometer tire gauge , need to put a couple psi, AAAACK! my chuck won't fit between the wheel and brake rotors to get on the valve stem........ a short right angle chuck is on order, be here Saturday

I just use the TPMS and don't bother with a tire gauge. But I do have a right angle chuck on my compressor hose as well as on my Slime mini compressor that I take with me when traveling. While I was at my 1348 mile motorcycle camping trip this weekend (just returned home today) I did have to add air to both tires so I put the AK on the center stand and ran the engine while using my mini compressor to add a few psi. Took all of 4 seconds per wheel to bring it up 3-4 psi each. I can plug my mini compressor in the SAE Battery Tender cable that I have with bigger wire and a 15 amp fuse (needed for the mini compressor).

[randyo]

I just use the TPMS and don't bother with a tire gauge. But I do have a right angle chuck on my compressor hose as well as on my Slime mini compressor that I take with me when traveling. While I was at my 1348 mile motorcycle camping trip this weekend (just returned home today) I did have to add air to both tires so I put the AK on the center stand and ran the engine while using my mini compressor to add a few psi. Took all of 4 seconds per wheel to bring it up 3-4 psi each. I can plug my mini compressor in the SAE Battery Tender cable that I have with bigger wire and a 15 amp fuse (needed for the mini compressor).

I coulda gone thru the work of getting my, yes I have a Slime too, compressor out, unravel the cord, and use that, then wrap it up and put it away. But I'd rather just grab the hose from my shop compressor, give it a squirt of air, and let the reel retract the hose, my Slime compressor is for the road

[rjs987]

I coulda gone thru the work of getting my, yes I have a Slime too, compressor out, unravel the cord, and use that, then wrap it up and put it away. But I'd rather just grab the hose from my shop compressor, give it a squirt of air, and let the reel retract the hose, my Slime compressor is for the road

Same here.
I use my bigger compressor with the 90 deg chuck in my garage and only use the Slime compressor on the road... which is where I was, 457 miles from home, when I did use it this weekend.

[rjs987]

On my return trip from my riding/camping trip to MN last weekend I discovered something about the factory TPMS on my AK 550. I think I may have seen this before but was then reminded of it. It was rather cool during most of that trip so I had added air to the tires to keep them at least close to where I like the psi to be. I knew the temps would warm up during the day so the psi would then become right where I wanted. On my return trip it started out very cool in the morning and the psi was just where I usually keep it for both tires. But after riding a short while the temps warmed up a little more than expected and I started getting a tire pressure warning. The tire profile symbol was flashing but neither of the tire symbols on the bike picture were flashing to indicate which tire was at fault. I then toggled the display to show what the psi was being indicated and the psi number for the front tire was flashing. The psi shown was higher than I usually see it at around 47 psi. That's rather high for the front tire. The rear tire was just barely  under 50 psi. These are HOT pressures so they SHOULD be higher than COLD pressures. But the front usually never gets over 45 psi while riding on a fast highway. So I stopped and let some air out until it showed 44.5 psi. That solved the fault indication. So the factory TPMS  does show an over pressure warning. This is a good safety feature same as showing under pressure. I guess in thinking on it any good TPMS should show both under pressure AND over pressure faults so it is good to know the TPMS on the AK does this.

[randyo]

On my return trip from my riding/camping trip to MN last weekend I discovered something about the factory TPMS on my AK 550. I think I may have seen this before but was then reminded of it. It was rather cool during most of that trip so I had added air to the tires to keep them at least close to where I like the psi to be. I knew the temps would warm up during the day so the psi would then become right where I wanted. On my return trip it started out very cool in the morning and the psi was just where I usually keep it for both tires. But after riding a short while the temps warmed up a little more than expected and I started getting a tire pressure warning. The tire profile symbol was flashing but neither of the tire symbols on the bike picture were flashing to indicate which tire was at fault. I then toggled the display to show what the psi was being indicated and the psi number for the front tire was flashing. The psi shown was higher than I usually see it at around 47 psi. That's rather high for the front tire. The rear tire was just barely  under 50 psi. These are HOT pressures so they SHOULD be higher than COLD pressures. But the front usually never gets over 45 psi while riding on a fast highway. So I stopped and let some air out until it showed 44.5 psi. That solved the fault indication. So the factory TPMS  does show an over pressure warning. This is a good safety feature same as showing under pressure. I guess in thinking on it any good TPMS should show both under pressure AND over pressure faults so it is good to know the TPMS on the AK does this.

I

I was once told that you should for a 10% rise in pressure but from a guy who only uses purple oil

[rjs987]

Maybe that works for car tires but I've always seen closer to 15-20% rise in psi from cold to hot for motorcycle/scooter tires depending on how hard I am riding, ambient air temps, road surface (actually has more do to with it than you would think), and speed. Oh, and also depending on degree of tire wear. As tires wear they will become slightly hotter due to slightly more rubber, uh, rubbing on the road causing the psi to go slightly higher.

That 50 psi for the rear tire was also a bit high but the TPMS didn't call it out as too high. Normally I see a hot pressure around 47 psi. I did stop a few times to let out just a little air at a time to avoid letting out too much.

[randyo]

Maybe that works for car tires but I've always seen closer to 15-20% rise in psi from cold to hot for motorcycle/scooter tires depending on how hard I am riding, ambient air temps, road surface (actually has more do to with it than you would think), and speed. Oh, and also depending on degree of tire wear. As tires wear they will become slightly hotter due to slightly more rubber, uh, rubbing on the road causing the psi to go slightly higher.

That 50 psi for the rear tire was also a bit high but the TPMS didn't call it out as too high. Normally I see a hot pressure around 47 psi. I did stop a few times to let out just a little air at a time to avoid letting out too much.

sounds more realistic than the purple oil guy, when I tried to get a 10% rise, I had to start at close to 50, I seem to remember setting the front on my SV650 @ 36 and hot it would be up to 42 and on a real hot day of riding agressive, up to 44, in the rear, I would start @ 39 and would climb as high as 48

a lot depends on the humidity of the air inside the tire, filled with nitrogen, and you won't see any pressure rise

[Stig / Major Tom]

Actually that is a false statement. The Honda CTX1300 user manual and service manual both show a factory recommended rear tire psi of 42. The pressure indicated on the sidewall of the OEM tires is also 42 psi. I always ran the rear tire on my CTX1300 to factory spec... 42 psi. I agree to never exceed the psi indicated on the sidewall of the tires which CAN result in a really bad day for the rider. But it is OK to go up to that with the understanding that the ride will be effected. Skilled riders know how to manage that without any issues. Higher inflation results in a slightly harder ride but better wear (based on experience over the last 19 years of paying very close attention to my tires). Lower inflation will result in a softer ride (which is what manufacturers want you to experience) but worse wear and possibly cupping (scalloping) of the tire (also based on experience over the last 19 years of paying very close attention to my tires). I rather like the slightly harder ride. But then I really never noticed much difference in that with low inflation vs higher inflation.

I stand corrected - you found a sidewall and a manual which agree (spooky that Honda is using tires running at the max!)

Simply - the sidewall figures state the maximum load and pressure for the tire, obviously - as determined by the tire manufacturer.
The correct PSI for the tire is found on a plate or sticker applied somewhere on the scooter, and in the owner's manual.

The correct PSI should never be determined by looking at the sidewall - look instead at the tag on the scooter - or in the manual.

Ride whatever PSI you want (see, 'Skilled Riders') - but the scooter is intended to be run with the tire size and PSI as stated in the manual, not the sidewall.

Let us all not misinform by stating the sidewall is where the correct tire pressure is found.

Most of the time the PSI on the sidewall is a little or a lot higher than stated in the manual!
My 25PSI front tire (tag&manual) has a 38PSI sidewall.....which would loosen my teeth.

Stig

[Iahawk]

Simply - the sidewall figures state the maximum load and pressure for the tire, obviously - as determined by the tire manufacturer.
The correct PSI for the tire is found on a plate or sticker applied somewhere on the scooter, and in the owner's manual.

The correct PSI should never be determined by looking at the sidewall - look instead at the tag on the scooter - or in the manual.

Let us all not misinform by stating the sidewall is where the correct tire pressure is found.

Stig

This!