DeTomaso Mailing List: June 97, Message #54
     



From: firanzi@erols.com (Jim Firanzi)

Subject: Re: Tires...need new...what size?

Date: Thu, 05 Jun 97 19:47:16 GMT



Dave,



Tire selection is more a matter of personal taste than of crunching numbers and 

coming up with a scientific 'best tire'.  I should know... I agonized over this 

same decision just last month.  Your final selection ends up being a compromise 

between tire diameter, compound, tread/section width and speed rating.



Tire diameter effects overall gearing as seen by the engine and rear tires.  

Original tires were 27" (27.05") in diameter.  Deviations from this number 

result in differences in speedometer accuracy and top end (if you are driving 

over 135 MPH.)  Smaller tires result in more engine revolutions per mile 

traveled, meaning slightly smaller gearing, a little less gas mileage in 5th, a 

little faster acceleration, a little more wear on the engine, and less top end 

speed.  Typical tire diameters in 15" range from a high of 27.1 to a low of 

24.5 with 25.4 being near the norm in a 50 series tire.  A profile of 60 was 

stock, resulting in the 27" diameter on a 15" rim.



Tire speed ratings ranging from H to Z aren't too important unless you plan to 

drive 130 or faster (like at Pocono.)



Compound and tread design (and sidewall stiffness) will affect performance at 

least as much as tread width, so are important considerations.



Tread width is as important from the 'looks' aspect as from a road performance 

consideration.  Wider is grippier around the turns given equal tire design, but 

puts more stress on your suspension and makes the car 'tramline' (or follow 

road imperfections) more, and makes turning at low speed (parking) more 

difficult.



If show is more important than go, the BFG Euro T/A's come in about the widest 

15" tire capable of being mounted on stock 8" rims, and can be found in a 

diameter near 27".  (275 or so width if I remember correctly.)  The drawback is 

they are H rated (130MPH max), which isn't a problem unless you are evading 

capture or running on a fast track.  Their sidewall is fairly soft, so they 

offer a comfortable ride while exibiting more tire roll in hard cornering (and 

loss of turn-in and steering quickness.)



So... what did I decide to buy?  I chose tire construction and profile over 

tread width / looks.  I am mounting Yokohama AVS Intermediates in 235/60/15 and 

215/60/15.  To me, this was the best compromise for street and Pocono use.  I 

chose the 26.1" diameter as the largest I could get in a street tire (most top 

end at Pocono).  The widest tread I could find in a 60 profile was 235 for the 

rears, so I elected to keep the stock offset between front and rear tires by 

going with 215 in the front.  (They are offered in 225 as well.)  The AVSi is a 

sticky compound, aggressive tread and stiff sidewall, probably only surpassed 

on the track/street by Pirelli P-Zero's.  (In a street tire anyway.)



Now, if I didn't need to drive several hundred miles to Pocono this year (or 

had a support vehicle to carry spare tires and wheels), I would have opted for 

the BFG R1's, a DOT legal race tire with assymetric sidewall construction, very 

aggressive tread design and compound, and assymetric tread design (inner and 

outer half totally different.)  <<  I may do this next year!@



Jim







On 6/5/97 2:42PM, in message <199706051842.OAA19464@hj.tvol.com>, dave aument 

<hooligan@redrose.net> wrote:



> All, 

> 

>   Time for new tires....What looks and works nice on the stock campys? Any

> and all suggestions would be appreciated.

> 

>                                         Thanks....Dave   #4262

>          

> 

> 

>           

> 

> 







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