Guest hodgie Posted March 7, 2006 Report Share Posted March 7, 2006 Chaps, Cars finally out of the bodyshop in a beautiful (well kind of) Java Green. Sure this one's been asked int he past numerous times as well and open to personal preference I guess, BUT anyway. Along with the MGF minilites, I need some new boots. Having done my research I can get hold of Eagle F1's at £33 a piece!! As can all of you at mytyres.co.uk!! That is tyre only of course, but still a bargain in my book. Thing is that's for 195/55/15's. I am happy with that on the fronts as I do not want the steering too heavy (heavy enough already), but what do you guys think about rears. Obviously if I stick with that size all round, I can chop and change as they wear, but with 4.0 litres under the bonnet I was thinking 205/225 might be more appropriate on the rear. What do you guys run and how do you find it? On the issue of heavy steering have any of you guys puts a grease nipple on your rack to lubricate it. Apparently this helps. I have already done the roller bearing conversion. Quote Link to post Share on other sites
Guest MAF260 Posted March 9, 2006 Report Share Posted March 9, 2006 What's the roller bearing conversion that you mention? Is it roller top mounts? I've been looking long & hard for these, but thought they were obsolete? Chaps, Cars finally out of the bodyshop in a beautiful (well kind of) Java Green. Sure this one's been asked int he past numerous times as well and open to personal preference I guess, BUT anyway. Along with the MGF minilites, I need some new boots. Having done my research I can get hold of Eagle F1's at £33 a piece!! As can all of you at mytyres.co.uk!! That is tyre only of course, but still a bargain in my book. Thing is that's for 195/55/15's. I am happy with that on the fronts as I do not want the steering too heavy (heavy enough already), but what do you guys think about rears. Obviously if I stick with that size all round, I can chop and change as they wear, but with 4.0 litres under the bonnet I was thinking 205/225 might be more appropriate on the rear. What do you guys run and how do you find it? On the issue of heavy steering have any of you guys puts a grease nipple on your rack to lubricate it. Apparently this helps. I have already done the roller bearing conversion. Quote Link to post Share on other sites
Guest hodgie Posted March 9, 2006 Report Share Posted March 9, 2006 What's the roller bearing conversion that you mention? Is it roller top mounts? I've been looking long & hard for these, but thought they were obsolete? The infamous S&S supplied them to me- I needed some directions for fitting! But they are merely sierra thrust bearings, or so I understand. I think I have fitted them properly :-) Steve also mentioned greasing the rack. Although it is a sealed unit, you can drill the big nut adjacent to the pinion and insert a nipple to force feed it grease. Haven't done this yet, but I gather that can help if the rack is less then well lubricated! Quote Link to post Share on other sites
mikehardwick Posted March 10, 2006 Report Share Posted March 10, 2006 The infamous S&S supplied them to me- I needed some directions for fitting! But they are merely sierra thrust bearings, or so I understand. I think I have fitted them properly :-) Steve also mentioned greasing the rack. Although it is a sealed unit, you can drill the big nut adjacent to the pinion and insert a nipple to force feed it grease. Haven't done this yet, but I gather that can help if the rack is less then well lubricated! Hodgie - got my thrusts from my local Ford dealer some years ago. Was surprised by your reference to the 'sealed' rack. Mine has a threaded hole fitted with a blanking plug in the location described which is factory spec I believe. I just pop in a nipple every 5000 miles and pump in some hmp grease. My workshop manual describes the operation and specifies grease (hmp) and quantity (5 pumps of the grease gun). BTE, I'm using 195/55x15 Eagles on the front and 205/50x15 on the rear of my 3.5. I would probably wan't the 205s if I had 4.0 litres. Mike Quote Link to post Share on other sites
saxchappy Posted March 11, 2006 Report Share Posted March 11, 2006 Hi! Permission to show my ignorance again? On this steering rack grease nipple issue, I enquired about getting the replacement plug with the nipple fitted and they are, apparently, scarce. Why can't you just take the straight blanking plate off, squirt in the required amount of grease and then replace the plug? No - don't laugh. One day I'm going to be able to answer somebody's problem Kevin Quote Link to post Share on other sites
rayjones Posted March 11, 2006 Report Share Posted March 11, 2006 Hi Kevin, I think the problem is that because of the small clearances inside the rack the grease does not go anywhere useful unless you are able to force it in under pressure from a grease gun via a grease nipple. Ray Quote Link to post Share on other sites
Guest hodgie Posted March 11, 2006 Report Share Posted March 11, 2006 I think Ray is right, you need the nipple to force the grease in. Simple answer to be honest, tap the big nut and screw in a nipple. Easy peasy. Mike, do you find it makes a big difference/helps out? I know that kind of depends how well lubed you are to start with! Re tyres, what'dya reckon. 205/50's rear and 195/55's front. Don't want it too slippy slidey, but I am putting some quality tyres on...... Quote Link to post Share on other sites
anthonyt Posted March 13, 2006 Report Share Posted March 13, 2006 If you only drive on sunny dry days what you propose should be ok. Unless you are buying some expensive road/track type tyres yokohama A032R Advans or similar you will find it a handful in the wet with 205's (and perhaps even then), i would go with the widest you can fit at the rear (with good water dispersal) if you want to get the hp to the ground. If you have spent the money on prettying things up it would be a shame to bend the car for the sake of the last couple of hundred quid. I now run 225 50 15 Advan A032R's on all corners on the street and 265 50 15 A032R's on the track on the rears, rear suspension will play a big part in wet weather handling also. (i dont have power steering) There are plenty of previous posts on the suspension topic my preference is 400lb fron and 250lb rear (standard mounting so efectively 195lb rear) for the street with standard sway bars. Tracks setups are a circuit by circuit thing. Quote Link to post Share on other sites
Cinnobar Posted March 13, 2006 Report Share Posted March 13, 2006 Oversize tyres on a given rim size will move around and give high speed instability. To be honest the real limitation ON THE ROAD is the suspension, as oversize rubber will just tax the rear suspension. Mine runs 195/60 x 14 on 6 x 14 rims 200Lb springs all round SPax adjustables & anti dive & NO rear anti roll bar & is fine on the public roads. Damn lethal in the wet but it would be anyway. A LSD would help as it would control the wheelspin. Quote Link to post Share on other sites
anthonyt Posted March 14, 2006 Report Share Posted March 14, 2006 That the tyres need to be on the right size rims is obvious??? I agree that the suspension will limit what you will get out of the tyres. You can fit 8" rims if you roll the inside lip of the guard which will give you 225 fitment (you can crib a half inch in the offset). i have raced with the 225's and 205's in the wet and found the 225's better and more controllable (if one is careful with the right foot and yes i have an LSD). Quote Link to post Share on other sites
Cinnobar Posted March 14, 2006 Report Share Posted March 14, 2006 Obvious Anthony, but he is starting with MGF wheels so may not be going wider on the rim, lots think that the wider the given tyre irrespective of rim width is better when in fact the opposite is usually the case. Not totally convinced that a track set up translates to the road on a 7 either. Quote Link to post Share on other sites
anthonyt Posted March 15, 2006 Report Share Posted March 15, 2006 I suppose that it depends upon how aggressively you drive and the mix of use! If you are into quick squirts in the countryside i would lean towards a soft track setup, if it is city driving etc a softer setup is better. I assumed that anyone bothering to put a 4litre lump in would be on the serious side of things thats all. Quote Link to post Share on other sites
martynharrison Posted March 16, 2006 Report Share Posted March 16, 2006 I'm running 195/50 all round and it suits me just fine. Wider tyres do not of themselves give an increased contact patch area and this combined with the coefficient of friction is what provides the literal grip. Hence a wide tyre has no more actual grip, all else being equal, contrary to popular myth. There are other reasons for fitting fat tyres, e.g. dropping tyre pressure to sacrifice tyre life for drag grip. Quote Link to post Share on other sites
jonlar Posted March 16, 2006 Report Share Posted March 16, 2006 How many use wider tyres just for the appearance? Quote Link to post Share on other sites
anthonyt Posted March 17, 2006 Report Share Posted March 17, 2006 "" Wider tyres do not of themselves give an increased contact patch area and this combined with the coefficient of friction is what provides the literal grip. Hence a wide tyre has no more actual grip, all else being equal, contrary to popular myth."" Sorry but you are wrong Martyn, i am not sure where this urban myth originated, contact patch varies with many factors including tyre, width, side wall strength, diameter, pressures etc. Stop and think about it for a moment why would race cars use wider tyres if they didnt need to? Extra width means extra weight, rolling resistance and many other negatives, if narrow tyres had the same grip F1 cars wouldnt use wide ones. As to wider tyre for appearance, to each their own, i once had a fellow wedge driver ask why i had four wheel discs, after i outbraked him for the fourth or fifth time on the track he came over and had a look at how i had fitted them so that he could modify his own car! Same goes for tyres if you dont think you need wider tyres dont buy them, the strength of forums is that they allow people to say what they have found in their experience, the reader can then decide what they want to do based on their own interpretation of the comments I have a number of very high performance cars and have found that wider tyres work better both on the road and the track, if anyone has found that there car performed better with skinnier tyres of the same compound i would be most interested to hear the story. Quote Link to post Share on other sites
jonlar Posted March 17, 2006 Report Share Posted March 17, 2006 "" Wider tyres do not of themselves give an increased contact patch area and this combined with the coefficient of friction is what provides the literal grip. Hence a wide tyre has no more actual grip, all else being equal, contrary to popular myth."" Sorry but you are wrong Martyn, i am not sure where this urban myth originated, contact patch varies with many factors including tyre, width, side wall strength, diameter, pressures etc. Stop and think about it for a moment why would race cars use wider tyres if they didnt need to? Extra width means extra weight, rolling resistance and many other negatives, if narrow tyres had the same grip F1 cars wouldnt use wide ones. But F1 cars wouldn't get the benefit of the tyre width, grip etc., if it wasn't for the extreme aerodynamics - they do say an F1 car could be driven upside down stuck to the ceiling of a tunnel, with the suction and downforce (reverse lift) created................. Quote Link to post Share on other sites
Guest croydebay Posted March 17, 2006 Report Share Posted March 17, 2006 But F1 cars wouldn't get the benefit of the tyre width, grip etc., if it wasn't for the extreme aerodynamics - they do say an F1 car could be driven upside down stuck to the ceiling of a tunnel, with the suction and downforce (reverse lift) created................. Love him or hate him, there is only one man who we can ask to test that one out... Jeremy Clarkson. Quote Link to post Share on other sites
martynharrison Posted March 17, 2006 Report Share Posted March 17, 2006 "" Wider tyres do not of themselves give an increased contact patch area and this combined with the coefficient of friction is what provides the literal grip. Hence a wide tyre has no more actual grip, all else being equal, contrary to popular myth."" Sorry but you are wrong Martyn, i am not sure where this urban myth originated, contact patch varies with many factors including tyre, width, side wall strength, diameter, pressures etc. Stop and think about it for a moment why would race cars use wider tyres if they didnt need to? Extra width means extra weight, rolling resistance and many other negatives, if narrow tyres had the same grip F1 cars wouldnt use wide ones. It's a myth that wider tyres give more grip in line with their width. Like I say, the contact patch area depends on tyre pressures anyway, not width of the patch. The pressure inside the tyre acting on the inside of the contact patch is clearly going to equal the pressure of the ground acting on the outside of the contact patch. Sure, sidewalls might introduce some modification to this but you have the same sidewalls regardless of tyre width and if the middle isn't taking the load width won't matter. What must happen is that when the tyre pressures are lower than the ground pressure, the tyre squishes out until it does. Similarly, pump up the tyres and they regain their shape and reduce the area of the ground contact. This can easily be messed about with to see that it really does happen this way. Now if you double the tyre width keeping the pressure the same, the width of the contact area doubles but the length halves. The contact area remains the same. The pressure on the outside of the tyre, times the contact area, equals the weight on the tyre. E.g. if the outside pressure is 20 pounds per square inch and the contact patch area is ten square inches, the weight of the tyre plus its load is 200 pounds. It doesn't matter if the tyre contact patch is 10 inches wide with about an inch of length or five inches wide with two inches of length. The relevant factors are the weight on the patch and the pressure between it and the road. This is also generally equal to the pressure inside the tyre but that's really only how you can increase and decrease the size of the contact patch more easily. Ignoring that aspect anyway, the pressure per square inch times the coefficient of friction for the materials (rubber and road) gives you the frictional limits. It's not important if this is 200 pounds spread over 10 square inches for 20 PSI times X times 10, or the same 200 pounds spread over 5 square inches for 40 PSI times X times 5, you get the same frictional limiting force. In the real world there are all sorts of factors that are well worth considering, none of which eliminate these generalisations but some of which make tyre width a worthy factor. Wide tyres can run a rounded patch that is larger by using a lower PSI. Wider tyres with low PSI can convert the surface rubber into smoke, changing temperature and therefore coefficient of friction and a wider tyre has more surface area to spend in this way. A wider tyre has a larger surface area so can be heated up more by flexing forces without overheating as the tyre radiates more heat to the air for a given temperature. And so on. The point about all this is there is nothing wrong in selecting wide tyres if you have a reason for doing that. Some size will be ideal and going larger will not be smart. It is not the case that a tyre twice as wide will therefore give twice the grip - that is just not how it works. Quote Link to post Share on other sites
Guest hodgie Posted March 18, 2006 Report Share Posted March 18, 2006 Whoa, system overload!! Yes, I plan to do some track days, but these tyres are for the road. It's a seriously powerful machine and I want to keep it in one piece and stuck to the road. Standard MGF minilite 15" rims. Adjustable spax set up with 200lb springs etc. Usual occasional track day set up. I am certainly no tyre expert, but I know that different cars react differently to different tyres, let alone different sizes. Large rears can cause understeer, increased tyre wear, clearance problems etc. And rather than go through the expense of trial and error, I thought we might have a consensus!! I am looking at Toyo Proxes TR-1's as they do a good fitment range (Goodyear Eagle F1's were preferred option but only do 195's in 15" rim size) and appear to be highly regarded for dry and (most importantly in our climate) wet grip, along with road noise etc (although to be honest can't hear anything over the engine growl Current plan is now revised to 195/50/15 on the front and 215/45/15 on the rear. Identical rolling radius (to each other), and close enough to standard, so no speedo probs there. Seems sensible to keep the fornt slightly narrower. Hopefully no-one objects, or tells me it will handle like a pig or foul the rear arches at that width?!? Quote Link to post Share on other sites
malcolm Posted March 18, 2006 Report Share Posted March 18, 2006 Hodgie. I've used 15" MGF wheels with 195/50 tyres on two V8 DHCs, both of which have had occasional track use. The current DHC has Falkens which seems to be working out well. After reading this perhaps I'll put something wider on the back next time, but to be honest the 195s have been fine. Having said this the current track FHC has always had 205s all round and it does have more grip. Not sure I'd go as far as 215s? Malcolm. Quote Link to post Share on other sites
anthonyt Posted March 19, 2006 Report Share Posted March 19, 2006 Hodgie the toyo proxies are a good tyre, great for hillclimbs where you want grip from the very start they dont like lots of track time as they tend to melt once you get too much heat into them, would be good enough for sprints (say 6 or so laps) and they are fine on the road. Quote Link to post Share on other sites
Guest hodgie Posted March 20, 2006 Report Share Posted March 20, 2006 What about width at the rear. 205/50/15 run a little fast. 215/45/15 are identical to the 195/50/15, I plan to put on the front, but will they clear the rear arch lips OK? Quote Link to post Share on other sites
anthonyt Posted March 21, 2006 Report Share Posted March 21, 2006 If you roll the inside lip up you should get away with it but it will depend upon your offsett and ride height. If you have the wheels with 195 and they fit with plenty of clearance now you should be ok. Quote Link to post Share on other sites
Guest hodgie Posted March 30, 2006 Report Share Posted March 30, 2006 If you roll the inside lip up you should get away with it but it will depend upon your offsett and ride height. If you have the wheels with 195 and they fit with plenty of clearance now you should be ok. OK for the record - The MGF (minilite style 15") wheels fit on no problem- no spacers required, a little tighter than the original 7 alloys but no problem. The tyres, Toyo Proxes Tr-1's all round 195/50/15 front and 205/50/15 rear. Actually loads of room and nowhere near the rear arches, so if i buy again in future, probably go to 215/45/15 (exactly same rolling radius as 195/50/15 on front) on the rear. Although if you need spacers, I guess this may affect things slightly. Hope that helps others. I'll tell you how they grip when she hits the road, but have to be better than the dross I was driving on previously!! Have to wire in the central locking this weekend, then get the alarm fitted, then she's ready to rock and roll (with a little dab of the right hand pedal P.s Attached a piccy of her pre spray job. Damn that attachment thing never works for me!! Quote Link to post Share on other sites
jonlar Posted March 30, 2006 Report Share Posted March 30, 2006 Damn that attachment thing never works for me!! Doesn't for me either! I've given up trying now. Quote Link to post Share on other sites
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