transam Posted June 20, 2017 Share Posted June 20, 2017 http://www.popularmechanics.com/cars/how-to/a3682/4281033/ Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 11 hours ago, Moonmoon said: sell it to the shop in exchange for this set. Yeah lots of s/h tyre shops knocking about. Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 2 hours ago, transam said: http://www.popularmechanics.com/cars/how-to/a3682/4281033/ I'm a bit critical of some of this tyre info sites for one nothing happened to the Yaris ABS it still works, not that it's ever use much. Link to comment Share on other sites More sharing options...
transam Posted June 20, 2017 Share Posted June 20, 2017 Just now, Kwasaki said: I'm a bit critical of some of this tyre info sites for one nothing happened to the Yaris ABS it still works, not that it's ever use much. Well yeh, but a fridge on wheels ain't an SUV or a pickup..... Link to comment Share on other sites More sharing options...
Moonmoon Posted June 20, 2017 Author Share Posted June 20, 2017 3 hours ago, transam said: The steering will feel better because you have lost sidewall height so reduced flex. thats exactly what i felt. Link to comment Share on other sites More sharing options...
transam Posted June 20, 2017 Share Posted June 20, 2017 2 minutes ago, Moonmoon said: thats exactly what i felt. It's the same as stock tyres being over inflated, takes away sidewall flex and so the steering feels lighter... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 20 minutes ago, transam said: Well yeh, but a fridge on wheels ain't an SUV or a pickup..... I remember the Yaris jelly mold description but your fridge one eludes me. Link to comment Share on other sites More sharing options...
transam Posted June 20, 2017 Share Posted June 20, 2017 5 minutes ago, Kwasaki said: I remember the Yaris jelly mold description but your fridge one eludes me. Weight, A/C.......... Link to comment Share on other sites More sharing options...
Moonmoon Posted June 20, 2017 Author Share Posted June 20, 2017 12 minutes ago, transam said: It's the same as stock tyres being over inflated, takes away sidewall flex and so the steering feels lighter... understood now. hence the advice for me to inflated them to 29PSI? as recommended by the sticker on the side of the car door. Link to comment Share on other sites More sharing options...
transam Posted June 20, 2017 Share Posted June 20, 2017 Just now, Moonmoon said: understood now. hence the advice for me to inflated them to 29PSI? as recommended by the sticker on the side of the car door. Well yeh for stock tyres, BUT, if you fit big wheels with lower profile tyres you cannot use these pressures if you ever ride dodgy roads....The tyre cannot absorb the forces if you hit a pot hole, the force will transmit to the wheel and may destroy it....My chum has the T-shirt... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 4 minutes ago, transam said: Weight, A/C.......... Sorry still don't get it my Vigo had taller, wider tyres and wheel spacer and ABS was still OK. Only ever used it once stopping in wet at some lights, if you used it too often l reckon it would dismantle the truck. Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 55 minutes ago, transam said: Well yeh for stock tyres, BUT, if you fit big wheels with lower profile tyres you cannot use these pressures if you ever ride dodgy roads....The tyre cannot absorb the forces if you hit a pot hole, the force will transmit to the wheel and may destroy it....My chum has the T-shirt... Yeah you've reminded me of some important info stuff because we went from 14 " to 17 " rims and l wanted psi info.. There is a calculation that was posted by " moonoverwatersomicorother " can't find at mo l think it's on one of my USB storage. From memory pressures were within 6 psi either way. The main concern about alloy rims that you mention was trucks fitting and using alloys rims designed for use on SUV/ cars etc. Forget what height of OP 's original tyre depth was on his 18" rims, going to 20" could affect a psi change but not by much l would say. Link to comment Share on other sites More sharing options...
fredob43 Posted June 20, 2017 Share Posted June 20, 2017 2 hours ago, Kwasaki said: Yeah you've reminded me of some important info stuff because we went from 14 " to 17 " rims and l wanted psi info.. There is a calculation that was posted by " moonoverwatersomicorother " can't find at mo l think it's on one of my USB storage. From memory pressures were within 6 psi either way. The main concern about alloy rims that you mention was trucks fitting and using alloys rims designed for use on SUV/ cars etc. Forget what height of OP 's original tyre depth was on his 18" rims, going to 20" could affect a psi change but not by much l would say. Toyota recommend 29psi for Dunlop tyres on 20 rims. 30psi on the 18" Bridgestone. Both all round. That's on a Fortuner. Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 26 minutes ago, fredob43 said: Toyota recommend 29psi for Dunlop tyres on 20 rims. 30psi on the 18" Bridgestone. Both all round. That's on a Fortuner. Yeah as l remember a minor change maybe because of tyre width & height differences. Link to comment Share on other sites More sharing options...
kartman Posted June 20, 2017 Share Posted June 20, 2017 Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 44 minutes ago, kartman said: Not that idiot again please. Link to comment Share on other sites More sharing options...
Kwasaki Posted June 20, 2017 Share Posted June 20, 2017 Found the post by " moonoveretcetc " he use to have fixed drive in floods thing a the top of Motors page. PSI calculations. So in order to know what the proper pressures should be, we need to know: 1. The car manufacturers’ recommended pressures for the OEM tyres. 2. The Load rating of the OEM tyres (e.g. 112V, 111H, 109S etc) 3. The Load rating of the new tyres.. If your changing to different profile tyres. The correct rule is: Adjust the OEM recommended PSI pressures by subtracting or adding the load rating of the new tyre from the load rating of OEM new tyre. Examples: If the OEM tyre is 109S and the new tyre is 112V, and the OEM pressure is 29PSI: 109 minus 112 = minus 3 29PSI minus 3 = 26 PSI If the OEM tire is 112H and the new tyre is 111R, and the OEM pressure is 32PSI: 112 minus 111 = +1 32PSI + 1 = 33 PSI. So obviously important to know what the OEM load of your vehicles OEM tyre. If you didn’t swap your spare tyre, you should be able to look at it to determine the OEM load rating that corresponds to the vehicle manufacturers recommended pressures. If your new load index works out at a full 6 points lower than OEM tyres, I would be very concerned that you’ve got an unsafe fitment (it sounds like you have a passenger car tyre on an SUV or pickup). Be careful out there when buying tyres. Link to comment Share on other sites More sharing options...
pgrahmm Posted June 20, 2017 Share Posted June 20, 2017 It's a personal preference.....I've always preferred 4x4 SUV's..... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 21, 2017 Share Posted June 21, 2017 14 hours ago, pgrahmm said: It's a personal preference.....I've always preferred 4x4 SUV's..... Also the right tyres and PSI. Link to comment Share on other sites More sharing options...
transam Posted June 21, 2017 Share Posted June 21, 2017 3 minutes ago, Kwasaki said: Also the right tyres and PSI. My chum who is high up in the LOS motor trade (and a race car driver) told me that using low pressure in big wheel low profile tyres in LOS on a heavy ride could be a disaster if you hit a pothole, the tyre cannot take the shock and it ends up at the rim... My friend put big wheels on his Vigo and that is what happened to him. The outer part of the rim broke off, the ride went all over the place and was very lucky no oncoming traffic. I did have a photo of the rim but can't find it... Link to comment Share on other sites More sharing options...
Moonmoon Posted June 21, 2017 Author Share Posted June 21, 2017 So are 29psi right for my tyres or not? after a few days of driving. ok this is what i feel. Better driving, response, left to right. slight more noise than 18" a more bumpier ride than b4. Any advice on how i can reduce the bumpy? not that its irritating or anything cos my HOnda Brio was alot bumpier than this. But if it can be better why not. Link to comment Share on other sites More sharing options...
transam Posted June 21, 2017 Share Posted June 21, 2017 3 minutes ago, Moonmoon said: So are 29psi right for my tyres or not? after a few days of driving. ok this is what i feel. Better driving, response, left to right. slight more noise than 18" a more bumpier ride than b4. Any advice on how i can reduce the bumpy? not that its irritating or anything cos my HOnda Brio was alot bumpier than this. But if it can be better why not. I think you are stuck with it...This is the downside of looking cool.... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 21, 2017 Share Posted June 21, 2017 2 hours ago, transam said: My chum who is high up in the LOS motor trade (and a race car driver) told me that using low pressure in big wheel low profile tyres in LOS on a heavy ride could be a disaster if you hit a pothole, the tyre cannot take the shock and it ends up at the rim... My friend put big wheels on his Vigo and that is what happened to him. The outer part of the rim broke off, the ride went all over the place and was very lucky no oncoming traffic. I did have a photo of the rim but can't find it... l take it you read the ID167 calculation post, l can only discuss events that have happened to me personally, that might take forever. With respect to your Thai friend l would say many things could be an eventuality in certain conditions and in tests there could be cause for things to happen one way or another according to the tyre construction and the rim but a lower pressure of 2 or 3 PSI most l guess would say it wouldn't make a lot of difference. As we know tyre road friction makes pressure gains with heat. l could easily assume your other friends experience could of been a premature failure of a faulty rim, it's certainly not unheard of also they buckle easily in accidents. l remember seeing your broken rim picture post taken in the back of a truck, if you go to top right and bring down your content list you may find it in :- My Attachments. l stand to be corrected but a heavy ride with the correct rim, correct tyre and PSI should be able to sustain hitting a road pothole without damage. The question would be how deep does a pothole have to be before tyre & rim failure. Why do we make problems for ourselves, you can't beat a good old solid bullet proof steel rim. Link to comment Share on other sites More sharing options...
pgrahmm Posted June 21, 2017 Share Posted June 21, 2017 Don't forget, tires are designed to flex in only certain areas of the sidewall..... Too little/under pressure to soften the ride & the flex moves closer to the wheel - allowing for rim damage as well as inside liner weakening due to bruising when the rim makes contact with the tire as the tire is absorbing road shock (doesn't have to be an extreme shock on low profile tires)..... Too much pressure moves the flex point closer to the road which might also create some over steer tendencies & rougher ride but is probably the more desirable of the two conditions.... I toured the Goodyear factory once & they showed how/what took place in tire failures & how they "read" the inside of the tires for warranty & legal interpretations/determinations..... It was pretty amazing & concise + very interesting......A side of the story we don't see.... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 21, 2017 Share Posted June 21, 2017 21 minutes ago, Moonmoon said: So are 29psi right for my tyres or not? after a few days of driving. ok this is what i feel. Better driving, response, left to right. slight more noise than 18" a more bumpier ride than b4. Any advice on how i can reduce the bumpy? not that its irritating or anything cos my HOnda Brio was alot bumpier than this. But if it can be better why not. If your 20" height profile tyre is lower than the 18" profile tyre, ride differences obviously will be noticed. Personally when l check tyre pressures about every month it's morning and for ride comfort driving around and about l put 3 psi less. Going trip l put the recomemded amount. Link to comment Share on other sites More sharing options...
transam Posted June 21, 2017 Share Posted June 21, 2017 As I posted my thoughts are related to Thai roads, not farang roads. Even serious off roadsters do not use low profile tyres, they use huge tyres with lots of sidewalls with low pressures so the tyre works for them.. We need a mathematician now...........Pickup, 2 tons, traveling at 80kph, hits a pothole and the tyre/wheel is connected to the hard edge of the road....What actually force is exerted on the tyre wheel combo....Fat tyre absorbs a lot, what happens with a skinny tyre, where does that force end up..... Link to comment Share on other sites More sharing options...
pgrahmm Posted June 21, 2017 Share Posted June 21, 2017 8 minutes ago, Kwasaki said: l take it you read the ID167 calculation post, l can only discuss events that have happened to me personally, that might take forever. With respect to your Thai friend l would say many things could be an eventuality in certain conditions and in tests there could be cause for things to happen one way or another according to the tyre construction and the rim but a lower pressure of 2 or 3 PSI most l guess would say it wouldn't make a lot of difference. As we know tyre road friction makes pressure gains with heat. l could easily assume your other friends experience could of been a premature failure of a faulty rim, it's certainly not unheard of also they buckle easily in accidents. l remember seeing your broken rim picture post taken in the back of a truck, if you go to top right and bring down your content list you may find it in :- My Attachments. l stand to be corrected but a heavy ride with the correct rim, correct tyre and PSI should be able to sustain hitting a road pothole without damage. The question would be how deep does a pothole have to be before tyre & rim failure. Why do we make problems for ourselves, you can't beat a good old solid bullet proof steel rim. You know - in some long boring drives here & with nothing else to do many times I'd watch the pot holes to see how bad they were..... It's amazing how many were at a foot or deeper - one close to or over 18" wheel I looked while walking out of curiosity - with abrupt edges...... I imagine more that a few have died at night in the rain on what must look like a solid road on their small motorcycles..... There is some very real danger on some of the roads here during the wet season & before pot hole filling season..... In the states I was a notorious night driver....Start in one area SF about 2-3AM and chug/check in in a couple of states away mid/late morning - early afternoon.....Faster speed limits there too & I usually ran 75-85MPH.... Not here - used too, but with the roads & a few elephants getting hit I just start about 6AM and make it a 2 day if I have to.... Link to comment Share on other sites More sharing options...
pgrahmm Posted June 21, 2017 Share Posted June 21, 2017 11 minutes ago, Kwasaki said: If your 20" height profile tyre is lower than the 18" profile tyre, ride differences obviously will be noticed. Personally when l check tyre pressures about every month it's morning and for ride comfort driving around and about l put 3 psi less. Going trip l put the recomemded amount. Good point here - don't overlook it....Smaller bodied tires are akin to a bicycle tire - high pressure & not much air volume....They should be checked monthly with the same gauge and adjusted - usually cold..... Don't let air out of a warm tire because they gain PSI through the constant heat from scrubbing & flexing - that is normal.... Plus you'll probably have one that loses air pressure a little faster than the others....You need to be aware if that's happening..... Link to comment Share on other sites More sharing options...
pgrahmm Posted June 21, 2017 Share Posted June 21, 2017 11 minutes ago, transam said: As I posted my thoughts are related to Thai roads, not farang roads. Even serious off roadsters do not use low profile tyres, they use huge tyres with lots of sidewalls with low pressures so the tyre works for them.. We need a mathematician now...........Pickup, 2 tons, traveling at 80kph, hits a pothole and the tyre/wheel is connected to the hard edge of the road....What actually force is exerted on the tyre wheel combo....Fat tyre absorbs a lot, what happens with a skinny tyre, where does that force end up..... About the only application that downsizes tires are for drifting - where they don't want traction + some low riders for aesthetics (not counting dragsters) .... The serious stuff gets serious tires..... Link to comment Share on other sites More sharing options...
Kwasaki Posted June 21, 2017 Share Posted June 21, 2017 26 minutes ago, pgrahmm said: There is some very real danger on some of the roads here during the wet season & before pot hole filling season.... Where we are people soon get on to local council about potholes, must say they do things quickly. That said potholes are very few on main roads here, bad ones are only on track roads off to some sightseeing places. Link to comment Share on other sites More sharing options...
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