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StillKickin
06-10-2014, 08:20 PM
I just replaced the front tires on my 2012RT with car tires. The pressure rating on the tire says up to 50#, I am running 30. The shop owner thought I should stick to CanAm recommendations for 18. That seems low to me as the tire is rated higher. It rides great at 30, I'm impressed with how much better it handles.
What are your thoughts about running that much higher than CanAm recommendations? I'm not inclined to let air out, but would of course with reason. Words of wisdom? :dontknow:

Chupaca
06-10-2014, 08:45 PM
This is a top subject here and I'm sure you will get a variety of answers. Not being one to use car tires one does have to consider several things. Your roadster is a tad lighter so there recommended pressures don't apply. Most start with the factory recommended and adjust from there. Now it will also depend on the brand and type of tires you are using. This could go on so hang in there for those using them...:thumbup:

sledmaster
06-11-2014, 09:40 AM
I really do not know if there is a correct answer here. I really believe it might be more of a case by case basis with the vehicle weight and exact tire being larger considerations. There should be many previous threads to search that will indicate what others have used for pressures, but most of them will be on the rear tire and not as many on the fronts. It is not really a black and white subject, but one of many factors.

Generally a MFG suggested pressure is based on a specific tire specification. Seeing how the OE Kenda tires are 2-ply tires and they are such more for ride comfort and reduced production expense, the oe suggested 15-17 psi seems low but it is adequate. Even with these tires many of us have run much higher pressures to get the machine to handle better and roll less in the corners, at the expense of ride quality. The 15-17 suggestion is also based on many other factors, from traction to sidewall flex to body roll to ride comfort to fuel economy to tread wear pattern to tire load rating.

To inflate a tire to the max rated pressure is usually only done if you are at the maximum load capacity of that tire, which we are not since the Spyder is such a light vehicle. Even on an automobile, when we install a tire with a higher load rating, it is common to run a higher pressure than what the suggested pressure is for the vehicle, but since the vehicle is "light" for the tire we do not run the pressure up to the max for the tire. No need to. Applied to the Spyder, it should then also be logical to run a higher pressure as we are installing a tire with a higher load rating, but nowhere near as high as the tire sidewall indicates. IMO.

Also consider how on a trailer, if you are not loaded to the maximum, we will often run a lower pressure than what the sidewall indicates, just to keep the thing from bouncing all over the place. Applied here, too much air in the car tires on a light vehicle will make the Spyder bounce around. A lower pressure will also let the tire squat some and give the tire more footprint on the road surface.

It really comes down to what seems to work for your preferences and riding conditions, IMO. Being a higher load rating tire, I tend to run higher pressures. It will help reduce the rolling resistance and give you better fuel economy, but we do not want to go so high that we sacrifice traction, which we might have already sacrificed due to a harder, longer lasting rubber compound.

I personally wouldn't go higher than 30, no need to with our light vehicle as the tire should never get hot enough. I now run 20-something in the front and 30-something in the rear. As long as you are somewhere in between the OE pressure for the stock 2-ply tires and the max pressure for that exact tire you should be OK, I would be in the 20s and not any higher than 30 just because of the vehicle weight. Watch your fuel economy and tread wear patterns, pay attention to if the front end breaks loose, see if the front end bounces around, all indicators that you might want to deviate from where you are at.

I realize this really does not answer the direct question, but gives us some of the variables to consider. Let's see if we can get others with thousands of miles on car tires up front to indicate what they are doing.

WaltH
06-11-2014, 09:57 AM
I run 30 psi on all three tires. I have been using car tires since 2008 (four Spyders) and have tried various inflation levels. There is no "correct" answer. Do what feels right.

syclemom
06-13-2014, 07:43 PM
I run 30 psi on all three tires. I have been using car tires since 2008 (four Spyders) and have tried various inflation levels. There is no "correct" answer. Do what feels right.wife been running car tires for 60000 or so 22psi. front 17 psi. rear , rear is 215/60-15 general Altimax RT
frt. and rear