So on a rear 18 a 40R will in theory give better response on twisties and finding the apex than a 35R on a TURBO but on a NA with stock brakes will require higher RPM to achieve same pull away.........WOW all that in one breath!
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Tires...what are you running?
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I think - and could be wrong that in the case of the SS we are working with a specific circumference as much as possible but changing the rim size, therefore mostly we are effecting sidewall height. In our case I think sidewall height will help in handling as long as we stay within the limits.
that will only apply as long as your sidewalls stay stiff enough.
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With the 295 45 18 on the rear it is like running a higher gear. Because of this with the SC I am able to control the spin better by making it harder to spin the wheel off the line. The taller sidewall also allows for more flex in the tire to get more grip at lower pressures. I have also noticed less tendance for roll around the back wheel in heavy turning. The tread stays flat on the surface because of the flex in the rear tire. Remember with a single rear tire we share the roll effect a motorcycle has around a tire. Look at a sling with stock size tires that has been running fast in the turns, you will see scuffing around the edge of the tire where it rolls up on the edge. When this happens the tire has less tread contact with the ground and the wheel becomes easier to spin.
In comparison I found the 305 30 20 to have a lot less traction while using the same tire set up under acceleration and in the turns. With the 305 it felt like I was spinng a spool because of the small sidewall was to ridged to grip.
On the front I am running shorter side walls because I want them stiff to better control the roll which improves turn in. -
I put a Nitto NT05 275/35x20 on the rear of my SL. It's pretty much out of tread after just 5,000 miles of hard driving (but not doing burnouts).
I won't be buying that one again. Traction was only marginally better than the stock Kenda. And it was miserable on anything other than clean dry pavement. But the slight increase in circumference did give me a more accurate speedometer.
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@gearhead - the Mickey Thompson ET Street-R 325/35R18 you have... I went to the site and it gives no numbers on OD. I was curious as you are the second person who has spoken about this tire on an 18" wheel. They have the OD listed as TBD. Know the approximate size?
I don't really use my SS when it's raining, but if you hit any wet roads, how does it hold up with that tire?... OK, I see on the site it's around 27X13.50R18, but this is an estimate.... so around 27".
How does it do with water on the roads?
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@gearhead - the Mickey Thompson ET Street-R 325/35R18 you have... I went to the site and it gives no numbers on OD. I was curious as you are the second person who has spoken about this tire on an 18" wheel. They have the OD listed as TBD. Know the approximate size?
I don't really use my SS when it's raining, but if you hit any wet roads, how does it hold up with that tire?... OK, I see on the site it's around 27X13.50R18, but this is an estimate.... so around 27".
How does it do with water on the roads?
Not much rain out here in Kalifornia... I don't risk any water with drag tires, DOT or not. If I were to run into any rain on the road with the MT ET Street-R -- I'd just park it where it's dry and hang out. I did run across some wet pavement with one of my other rear tires, a Mickey Thompson Sportsman SR (in 26x12x18). Wet, that tire felt like the stock base model Kendas -- squirmy and greasy. And, the MT Sportsman SR's are steel belted all weather rated and have a pretty good and deep tread pattern. The rear end of the Slingshot is very light, so even the best of tires would be challenged in the rain. The weather apps have become pretty good, so you can accurately predict rain ahead of time. If you do get a MT Street-R, keep your other rear wheel/tire (you'll have to get another rim in 12x18 with a +45mm offset for the MT Street-R's anyway). If you anticipate rain, just swap wheels. If it's going to be dry, run with the drag tire. If you're planning on going on any long trips, you probably wouldn't wanna run the MT Street-R's -- they're glass belted and have little puncture resistance.
Hope this helps...
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Not much rain out here in Kalifornia... I don't risk any water with drag tires, DOT or not. If I were to run into any rain on the road with the MT ET Street-R -- I'd just park it where it's dry and hang out. I did run across some wet pavement with one of my other rear tires, a Mickey Thompson Sportsman SR (in 26x12x18). Wet, that tire felt like the stock base model Kendas -- squirmy and greasy. And, the MT Sportsman SR's are steel belted all weather rated and have a pretty good and deep tread pattern. The rear end of the Slingshot is very light, so even the best of tires would be challenged in the rain. The weather apps have become pretty good, so you can accurately predict rain ahead of time. If you do get a MT Street-R, keep your other rear wheel/tire (you'll have to get another rim in 12x18 with a +45mm offset for the MT Street-R's anyway). If you anticipate rain, just swap wheels. If it's going to be dry, run with the drag tire. If you're planning on going on any long trips, you probably wouldn't wanna run the MT Street-R's -- they're glass belted and have little puncture resistance.
Hope this helps...Awesome. Yes. I usually don't drive it in the rain, but never know. Want to do some longer trips this next year, so was just curious and want a larger tire as I can spin the stock 255 wheel in 1-2-3 with traction control on and really want a wider tire. I'll be going to some sort of engine upgrade as soon as I have the wheels, shocks and cosmetic upgrades I want.
Thanks again!
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I want to second your observation on tire size. As my Toyo 345/25/20 fits just fine and a Toyo R888r 335/30/18 that was shipped to me wrong did not look like it was going to fit. My 305/35/18 R888 installed for track days is only slightly less wide than my 345 Toyo.Try to get exact width measurements of each tire when you go over 305 in size.
@Slingrazor and @TravAZ -- Slingrazor, I know you are running the 295 on the stock and you love it, and Trav, you're running the larger. Can you safely run the 345 in the twisties, or do you recommend dropping down to the 295/305/315? As in, instead of having a "track" set and daily driver, should I plan to have a "twisty" set and daily? Is there a significant difference in handling between the 295/305/315?
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@Slingrazor and @TravAZ -- Slingrazor, I know you are running the 295 on the stock and you love it, and Trav, you're running the larger. Can you safely run the 345 in the twisties, or do you recommend dropping down to the 295/305/315? As in, instead of having a "track" set and daily driver, should I plan to have a "twisty" set and daily? Is there a significant difference in handling between the 295/305/315?
So I don't get confused. Are you wanting to run an 18 inch wheel on the back or a 20. That would make a difference on my answer.
My general opinion is to set your sling up to run on the road unless you spend a lot of time on the track. I would then do as Travis and have an extra set of wheels and tires.
I am really jealous of the Travis's ability to track often. I have no tracks available in Arkansas. -
The biggest issue with the Slingshot is traction out of the corner. A 345 Toyo works great for both cruising around and driving hard in the twisties. My street setup will never be as good as my track setup, because the track tires are an R compound and made for driving on the track.
A Toyo 345/25/20 T1R is safe, but you need to decide what rim/tire combo works best for you.
There are very few options in good directional tires over 305. So you wont have many options. This also gets tricky, when you need to decide how wide of rear wheel you are going to order.
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We have settled on a 20x12, but are keeping the stock rear as well. Will be running a 345 on the 20 to start, but not wedded to staying there. Just trying to educate myself on options knowing that size and tire choice affect capabilities.
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We have settled on a 20x12, but are keeping the stock rear as well. Will be running a 345 on the 20 to start, but not wedded to staying there. Just trying to educate myself on options knowing that size and tire choice affect capabilities.
@Slingrazor, what started this whole discussion is that I have a stock (Kenda) 305 in my garage from a 2017 SLR. Can't use it right now, as I have stock rims. My 2016 machine with the 20x9 has the Kenda 255 on it, and I had planned to go up to a Nitto 275 on it when this Kenda wears out. But @sideseatdriver wanted to look at what it would take to mount the 305, so she was looking at 20x11 and 20x12 wheels, and it now appears we have kind of fallen into a deal on a 20x12 wheel, WITH a 345 already mounted.
Confusing, I know.
So, it looks like we'll take the 20x12, run the 345 that's on it, then run the 305 that's just sitting in my garage, and at some point, decide what we want to do after both of those are gone.
In the meantime, I will keep my stock 18" front wheels, (and by the way I have two additional sets of Kenda 225s for those wheels), and eventually, someday, maybe will end up with front wheels to match this 20x12 we're picking up.
I think her eyes were opened a little bit on this trip to Murphy last weekend, on just how hard you can run the machine in the curves without any special super-whamodyne gear, and still feel fairly safe, so we're having the discussion about road vs. track because some other folks (who probably push their Slings way harder than I do) were making some interesting points about the differences.
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We have settled on a 20x12, but are keeping the stock rear as well. Will be running a 345 on the 20 to start, but not wedded to staying there. Just trying to educate myself on options knowing that size and tire choice affect capabilities.
The only issue I see with the 20X12 wheel (assuming the offset is correct) is the rear shock clearance. I'm using the 345/25/20 and it's on an 11 1/2 inch wide wheel. The rear shock clearance is about 1/4" using the QA1 shocks and can't recall what springs. Clearance has to be there or you're going to risk rubbing the tire at lower pressure going into hard turns
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Most 305 tires are not recommended to be installed on a 12inch wide wheel. You may be able to "get away" with it, but you will probably want to research this more before doing this. In most cases max wheel width for a 305 is 11.5 inches.
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The only issue I see with the 20X12 wheel (assuming the offset is correct) is the rear shock clearance. I'm using the 345/25/20 and it's on an 11 1/2 inch wide wheel. The rear shock clearance is about 1/4" using the QA1 shocks and can't recall what springs. Clearance has to be there or you're going to risk rubbing the tire at lower pressure going into hard turns
I have the QA1s as well, and it is a concern for me also, but not so much that I think I can't overcome it. I assume your wheel is centered? Is there any gain to be made by offsetting it another 1/4" or so to the left?
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The only issue I see with the 20X12 wheel (assuming the offset is correct) is the rear shock clearance. I'm using the 345/25/20 and it's on an 11 1/2 inch wide wheel. The rear shock clearance is about 1/4" using the QA1 shocks and can't recall what springs. Clearance has to be there or you're going to risk rubbing the tire at lower pressure going into hard turns
Great point. The only shock setup that hasn't worked with the Toyo 345/25/20 in the new Polaris Billstien shocks. Stock, QA1, JRi, have all worked fine.
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I have the QA1s as well, and it is a concern for me also, but not so much that I think I can't overcome it. I assume your wheel is centered? Is there any gain to be made by offsetting it another 1/4" or so to the left?
yes, it's centered. I'm not sure just how much of an issue you'd have if you wonder from the 45mm offset. I'm sure a couple of mm shouldn't be an issue under normal running conditions, but not sure how much further from stock you could go before it's a noticeable issue
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Anyone try the RidetechShockwaves with a 345? I'm guessing it won't fit, but not sure how close it is. Only one I know running them is @WraithSS, but he's got a 315 on the back. @WraithSS, how wide are those shocks in comparison to the stock? Do the bags interfere with he tire clearance what so ever? Have any pictures of your ass end
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@KayTwo, @sideseatdriver
I think your plan is solid on the 20 x 12, just make sure the tire you select provides tge grip you desire. Travis will have the best information on that setup.
I chose not to go bigger and wider on the rear tire because from my experience running a 305 30 20 had less traction than a 285 35 18. I believe their is a point having a wider tire spreads the contact area psi of the tire to thin. With the light weight of the slings back end, we are limited to the psi already. At what point the wider tire' s contact area starts to degrade traction is the unknown.
