Tire Pressure Science

[tbohman56]

Is there any science behind the suggestion to use 18-20 lbs of pressure in the front tires when using an auto tire? You know like some some calculation based on the vehicle weight and tire load specs? Or is it all based on individual rider experience and how the bike handles and feels on the road?

[RICZ]

The test I would use, if I were this picky, is to apply something on a small prtion of tread that will transfer to a flat, smooth medium. If, after driving the wheel across, the full width of the tread leaves an even imprint, that's the correct pressure.
Or you can simply go by feel.

[GFrog]

You know like some some calculation based on the vehicle weight and tire load specs? Or is it all based on individual rider experience and how the bike handles and feels on the road?

In theory, a little bit of everything you stated. Manufacturer recommended tire pressures are based on the average rider and average extra equipment, average temperature, average elevation, average road surface and condition, average vehicle handling, average etc... I'm sure you get my point.

The recommended tire pressure is a starting point. Then you adjust based on all the factors mentioned above. (it takes time)

Here is a really good video that explains the actual science behind deciding the correct tire pressure. This video is from a GP Bike Racer, but the science is the same and he also covers regular road bikes.

Have a look and then tests for all "Your" conditions and adjust accordingly. Good luck.

https://youtu.be/XaIuWKfnGEI

[BLUEKNIGHT911]

Is there any science behind the suggestion to use 18-20 lbs of pressure in the front tires when using an auto tire? You know like some some calculation based on the vehicle weight and tire load specs? Or is it all based on individual rider experience and how the bike handles and feels on the road?

Yes .....lots and lots ...... and yours or anyone else's Butts are not Science .....Mike

[Steve W.]

Yes, there is a bit of science, but most of that applies to what the manufacturer might call "intended use".

The cars for which the tires are intended weigh considerably more than any Spyder, so you can deduce that pressures for the Spyder would be less than for the cars. HOW MUCH less gets into the "guesswork and experience" category.

That is when you will have to trust all the ones that have done it before you, and use that as YOUR starting point to start your own experiences.

.

[UtahPete]

Yes, there is a bit of science, but most of that applies to what the manufacturer might call "intended use".

The cars for which the tires are intended weigh considerably more than any Spyder, so you can deduce that pressures for the Spyder would be less than for the cars. HOW MUCH less gets into the "guesswork and experience" category.

That is when you will have to trust all the ones that have done it before you, and use that as YOUR starting point to start your own experiences.

.

Well said.

[BLUEKNIGHT911]

Whoa Steve ..... there is a lot more than a bit of science involved in this ..... I spent months in school learning to become a certified " accident investigator " .. ( for my Police dept. ) .... The tires can be the determining factor as to " WHY this accident occurred ..... so, many many days were spent on " just ties " .... I've seen lots of video's / films ( which were proprietary and not available to the general public ) .... which showed how tires reacted to dozens of variables under varied weather conditions .... The advice Peter and I supply are based on this Science ..... and are fairly accurate considering they are aimed at the general user..... Hope this is useful info ..... Mike

[UtahPete]

Yes .....lots and lots ...... and yours or anyone else's Butts are not Science .....Mike

Unless their butts are the subject of scientific inquiry, of course...

[2dogs]

Is there any science behind the suggestion to use 18-20 lbs of pressure in the front tires when using an auto tire? You know like some some calculation based on the vehicle weight and tire load specs? Or is it all based on individual rider experience and how the bike handles and feels on the road?

Short answer, yes & no. Go search Tire PSI on this site and make a conclusion from that info.

[shakin_jake]

Is there any science behind the suggestion to use 18-20 lbs of pressure in the front tires when using an auto tire? You know like some some calculation based on the vehicle weight and tire load specs? Or is it all based on individual rider experience and how the bike handles and feels on the road?

~~~IIRC the tires on the 2019 Ryker Rally were identical on the 2020 Ryker Rally I rode and owned (since traded in on a 21’ Spyder RTL). I’m curious if the question you pose here has anything to do with the Ryker Rally or, the front tires used on Spyders, which seems to be the general dogma discussed regarding front tire pressure


Best,


Jake
Reddick Fla.
It’s never too late to have a happy childhood

[Mikey]

Short answer, yes & no. Go search Tire PSI on this site and make a conclusion from that info.

And take a couple aspirin before you start, you'll need them!!!!

[tbohman56]

~~~IIRC the tires on the 2019 Ryker Rally were identical on the 2020 Ryker Rally I rode and owned (since traded in on a 21’ Spyder RTL). I’m curious if the question you pose here has anything to do with the Ryker Rally or, the front tires used on Spyders, which seems to be the general dogma discussed regarding front tire pressure


Best,


Jake
Reddick Fla.
It’s never too late to have a happy childhood

Yes, it does have to do with the Ryker Rally. Just replaced front tires with 165/50R16 and only one other person (that I know of) has made this change on the Ryker.

[shakin_jake]

Yes, it does have to do with the Ryker Rally. Just replaced front tires with 165/50R16 and only one other person (that I know of) has made this change on the Ryker.

~~~Roger that, thank you


Best,


Jake
Reddick Fla.
Even a blind squirrel finds a nut every once in awhile

[jaherbst]

It is all smoke and mirrors! ( and what all the self appointed experts say on the forum ) I would go along with the manufacturers suggestions and good common sense which today seems a little hard to find. The absolute pressure is kind of like picking the Fly Specks

out of the "sugar bowl". Opinions on tire pressure are like noses, everyone has one.

Jack

[troop]

It is all smoke and mirrors! ( and what all the self appointed experts say on the forum ) I would go along with the manufacturers suggestions and good common sense which today seems a little hard to find. The absolute pressure is kind of like picking the Fly Specks

out of the "sugar bowl". Opinions on tire pressure are like noses, everyone has one.

Jack

Sooo... You're saying that even with car tires, you'd go 15-17# front (OK) and 28# rear? Or would you use the car tire MFR pressure ratings of 35# ??

[MNF3]

Yes. Start there (18 on rear). Drive for 30 min or more to get tires warmed up. If you see 4 psi increase warm over cold you’re golden. Less than 4psi increase you are over-inflated, and vice-versa.