setup wheels
12-14-2013, 08:25 AM
#1
Three Wheelin'
Thread Starter
setup wheels
been contemplating different setup wheel packages for handling alignments on the cup cars and RSR.
a few guys have been great enough to share ideas, etc. The dudes from Hubstands have emailed or posted their ideas and suggestions.
Been talking and working with VelocityHaus.
and if anyone has any photos or other things they'd love to share, would love to hear it.
\Thanks.
a few guys have been great enough to share ideas, etc. The dudes from Hubstands have emailed or posted their ideas and suggestions.
Been talking and working with VelocityHaus.
and if anyone has any photos or other things they'd love to share, would love to hear it.
\Thanks.
Last edited by spg993tt; 12-15-2013 at 02:49 PM.
12-14-2013, 01:41 PM
#2
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You should check out the setup wheels Gregg Pizzo makes (here's the link). They aren't low cost but he has load cells built in and a controller. It allows you to jack your car up in an exact spot each time and set the base parts under your setup wheels when you want to check your setup, rather than having pontoons built up all weekend.
http://velocityhaus.com/set-up-tools...s-gt-cars.html
Mark
http://velocityhaus.com/set-up-tools...s-gt-cars.html
Mark
12-15-2013, 02:35 PM
#3
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OK, this will be a rather long post, but I think the genuine question deserves it. Started to type an PM, so not some vendors would feel bashed, but decided it would probably be good for others to gain from the info and if some feels steeped on the toes, so be it. If you put a system on the open market, you should be able to handle criticism.
First of all, to give some background, I'm a professional motorsport mechanic with 25 years of experience here in Europe, a large portion of that spent with Porsche's, everything from factory stuff down to national GT/Carrera Cup effort, so I'm not just an internet warrior with one old 928 to have as a knowledge base.
Since you obviously put some effort behind your car/team to be professional, I'll give advice based on that. This is not for someone who bought an old cup to have as a track day toy, this is for someone trying to it in the best possible way to give himself the best tool available for racing (tool in this case is the car). Btw, every single part in a professional striving team I judge as a tool to make the team better, including the driver (and yes, he/she can also be a real tool, but that's something else...).
Firstly, talking about the setup platform itself, the way to go nowadays is to use 4 individual platforms for each wheel. The reason for the pontoons/bridges or whatever you may call them, was that with the early cups there was quite a lot of rubber in the suspension. There was a big problem with repeatability in setup, so that kind of system was created by mostly german teams to overcome that, since you could roll the car up directly from running on the track, without lifting the car and unloading the suspension. Now with the modern cups that are all steel in the suspension the problem doesn't exist anymore, hence there's no need for those big cumbersome things anymore. So go for 4 separate ones. Height is depending on what kind of setup wheels you go with. If you use real wheels and tyres, you need high platforms, otherwise you can get away with using low ones.
Secondly, never EVER do setup on standard scales. They WILL bend and give you false readings on ride heights. Either do setup first and then go up on the scales to finish off with cornerweights, or use the more expensive scales with multiple loadcells (or setup wheel/patches with built in poadcells). In my point of view teams that do full setups on regular scales have no clue what it takes to play with the big boys. Harsh but true.
Thirdly, if using a real rim/tyre, you must use slide plates. Not having them or using plastic bags is not acceptable, it creates unwanted sideloads on the suspension, it doesn't settle as it should do. 2 aluminium plates with grease in between or 1 alu and 1 PTFE plate is fine. Rolling the car off and on instead is not good enough.
Finally the setup wheels then. 2 ways of doing on this level IMO, either you use a dedicated set of real rims and tyres or you go with the machined "setup wheel". The big decider on this is if you run in a series with a set minimum rideheight and you tend to run close to that limit, like smaller than 2mm. If so, definitely go with rims, otherwise you'll never be sure if you're legal or not. When you're chasing the last tenth of a millimeter on rideheight to get that optimum performance you can not trust that the setup wheel has the correct pivot point, so it'll always be spot on in rideheight when you're changing camber. This is a very important question for your choice.
Rims: pros is that you're always sure on the correct rideheight. Cons is that they are more cumbersome to work around on a GT/touring car and to transport. The rims should preferable be brand new, never run and have the lip machined down in a lathe to give you a more exact point of measurement for camber/toe that you also know is dead flat (out of the box rims are so/so). Use a used set of slicks with zero pickup on them, used down to the maximum wear you calculate for a race set, this to give you a safety against being under rideheight if measuring on a new set. Always use them in the same place on the car and clock them in the same position every time, I normally put the valve at 6 o'clock. NEVER EVER use them on track or for transporting, then you just destroyed your repeatability.
Setup wheels: pros is that they're easier to work around, especially on a car with a body and easier to transport. Cons is that it's impossible to be a 100% reliable on rideheight with a changing camber. The tyre on a real wheel squashes depending on the sideload from the camber, that's impossible to replicate with a ballbearing that's solid. You can adjust it to be correct at a given camber but if you'll change the camber from the one you adjusted the base setting on the setup wheel with, it WILL be incorrect. If it's small enough difference to live with, that is up to you to decide, mostly depedending on that mimimum rideheight. If you use the rideheight just to have a reference point, then there's no problem at all.
Lastly and here's where it gets ugly, construction of said setup wheel. The one Mark linked to is mostly correctly constructed. It has a stiff construction for side loads, as the weight of the car, which is pretty big in the rear of a Porsche, is not inconsiderate. The "wheel" WILL bend/flex if just done in a fairly thin flat piece of aluminium and give you inconsistent reading. Also the pivotpoint where it stands on the platform needs to be in the same position as a genuine tyre, i.e. it needs to be inwards of the bolt flange for the rim, because on any real race car you run a healthy degree of camber. If said setup wheel is done in a straight line down from the flange, it's so missing the point of what it's supposed to be doing it's ridiculous. I prefer to see an adjustability sideways on the pivotpoint so camber/rideheight issues can be dialed out, that's the only thing I see "wrong" with the Velocityhaus ones, Porsche's OEM one has that feature and several others too. The other ones, that already have been in contact with you I consider to be utter garbage, without even seen them IRL. They will bend, the pivot point is in the wrong place and the bottom "wings" is material you will pay for, that does absolutely zero, just add to the cost. I realize they have a function on the cheaper ones without the ballbearing, those with the rubber patch, but those are even worse designwise with that rubber, so why keep it when it was redesigned?!
Just my humble opinions,
Uncle Grumpy
First of all, to give some background, I'm a professional motorsport mechanic with 25 years of experience here in Europe, a large portion of that spent with Porsche's, everything from factory stuff down to national GT/Carrera Cup effort, so I'm not just an internet warrior with one old 928 to have as a knowledge base.
Since you obviously put some effort behind your car/team to be professional, I'll give advice based on that. This is not for someone who bought an old cup to have as a track day toy, this is for someone trying to it in the best possible way to give himself the best tool available for racing (tool in this case is the car). Btw, every single part in a professional striving team I judge as a tool to make the team better, including the driver (and yes, he/she can also be a real tool, but that's something else...).
Firstly, talking about the setup platform itself, the way to go nowadays is to use 4 individual platforms for each wheel. The reason for the pontoons/bridges or whatever you may call them, was that with the early cups there was quite a lot of rubber in the suspension. There was a big problem with repeatability in setup, so that kind of system was created by mostly german teams to overcome that, since you could roll the car up directly from running on the track, without lifting the car and unloading the suspension. Now with the modern cups that are all steel in the suspension the problem doesn't exist anymore, hence there's no need for those big cumbersome things anymore. So go for 4 separate ones. Height is depending on what kind of setup wheels you go with. If you use real wheels and tyres, you need high platforms, otherwise you can get away with using low ones.
Secondly, never EVER do setup on standard scales. They WILL bend and give you false readings on ride heights. Either do setup first and then go up on the scales to finish off with cornerweights, or use the more expensive scales with multiple loadcells (or setup wheel/patches with built in poadcells). In my point of view teams that do full setups on regular scales have no clue what it takes to play with the big boys. Harsh but true.
Thirdly, if using a real rim/tyre, you must use slide plates. Not having them or using plastic bags is not acceptable, it creates unwanted sideloads on the suspension, it doesn't settle as it should do. 2 aluminium plates with grease in between or 1 alu and 1 PTFE plate is fine. Rolling the car off and on instead is not good enough.
Finally the setup wheels then. 2 ways of doing on this level IMO, either you use a dedicated set of real rims and tyres or you go with the machined "setup wheel". The big decider on this is if you run in a series with a set minimum rideheight and you tend to run close to that limit, like smaller than 2mm. If so, definitely go with rims, otherwise you'll never be sure if you're legal or not. When you're chasing the last tenth of a millimeter on rideheight to get that optimum performance you can not trust that the setup wheel has the correct pivot point, so it'll always be spot on in rideheight when you're changing camber. This is a very important question for your choice.
Rims: pros is that you're always sure on the correct rideheight. Cons is that they are more cumbersome to work around on a GT/touring car and to transport. The rims should preferable be brand new, never run and have the lip machined down in a lathe to give you a more exact point of measurement for camber/toe that you also know is dead flat (out of the box rims are so/so). Use a used set of slicks with zero pickup on them, used down to the maximum wear you calculate for a race set, this to give you a safety against being under rideheight if measuring on a new set. Always use them in the same place on the car and clock them in the same position every time, I normally put the valve at 6 o'clock. NEVER EVER use them on track or for transporting, then you just destroyed your repeatability.
Setup wheels: pros is that they're easier to work around, especially on a car with a body and easier to transport. Cons is that it's impossible to be a 100% reliable on rideheight with a changing camber. The tyre on a real wheel squashes depending on the sideload from the camber, that's impossible to replicate with a ballbearing that's solid. You can adjust it to be correct at a given camber but if you'll change the camber from the one you adjusted the base setting on the setup wheel with, it WILL be incorrect. If it's small enough difference to live with, that is up to you to decide, mostly depedending on that mimimum rideheight. If you use the rideheight just to have a reference point, then there's no problem at all.
Lastly and here's where it gets ugly, construction of said setup wheel. The one Mark linked to is mostly correctly constructed. It has a stiff construction for side loads, as the weight of the car, which is pretty big in the rear of a Porsche, is not inconsiderate. The "wheel" WILL bend/flex if just done in a fairly thin flat piece of aluminium and give you inconsistent reading. Also the pivotpoint where it stands on the platform needs to be in the same position as a genuine tyre, i.e. it needs to be inwards of the bolt flange for the rim, because on any real race car you run a healthy degree of camber. If said setup wheel is done in a straight line down from the flange, it's so missing the point of what it's supposed to be doing it's ridiculous. I prefer to see an adjustability sideways on the pivotpoint so camber/rideheight issues can be dialed out, that's the only thing I see "wrong" with the Velocityhaus ones, Porsche's OEM one has that feature and several others too. The other ones, that already have been in contact with you I consider to be utter garbage, without even seen them IRL. They will bend, the pivot point is in the wrong place and the bottom "wings" is material you will pay for, that does absolutely zero, just add to the cost. I realize they have a function on the cheaper ones without the ballbearing, those with the rubber patch, but those are even worse designwise with that rubber, so why keep it when it was redesigned?!
Just my humble opinions,
Uncle Grumpy
12-15-2013, 07:57 PM
#5
Rennlist Member
Try these guys, they're the ones I'm planning to get when my shop is finished..
http://www.mktechnologies.com/
And thanks for the tips uncle...
http://www.mktechnologies.com/
And thanks for the tips uncle...
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12-17-2013, 03:11 PM
#8
Racer
Some additional set up thoughts:
It’s all about measurements that you can repeat precisely, continually.
It’s about the accuracy of the changes you make; the accuracy and repeatability of the baseline values and the repeatability of the changed values. Making an accurate, precisely measured change from an accurate precise baseline that gives you the same, not close, value; the exact repeatable measurements every time. You can’t get that precision at tires. Think of tires like a set of water balloons. They are inherently inaccurate and always changing. That’s why so many serious racers and teams have gotten rid of the tires, gotten rid of their control wheels and measure everything at the hubs on stands, every time. If “you are playing with the big boys” and look for camber values within a tenth of a degree or ride height within a tenth of a millimeter. Stands not tires.
As McRae noted, the camber pivot point of the hub with the wheels and tires in place is further inboard than on the center line of the hub face. It is at a variable point between the wheels backspace edge and the tire’s inner shoulder. It’s near the inside boundary of the contact patch and because the tires vary and squish, so does this point. On the other hand, the centerline of the hub never changes. Again, why would you measure camber at the tire when it’s only repeatable to within a few tenths. The pivot point and camber measurement on stands at the hub is always the same; until you decide to change it.
At the tolerances McCrea describes, the strength of the pad levelers or wheel stands is important. Get good ones, assign them to a specific corner. Get a good pad leveling device. Check the level a lot. If your set up pad is off, everything on it is off.
The critical element with scales is their repeatable accuracy not the number of load cells or strain gauges. Scales registered to be 0.1% accurate used under a 2400 lb car will be within 7.2 ounces per corner, that’s pretty precise. A tire with rubber pick up is more than that.
Specifically for McRae: you trashed my product, ProHUBStands without using them, talking to us, talking to users or even simply seeing them. You pretend to be a professional but that “honest criticism” was pretty amateur and arrogant behavior. Send me your address and Ill ship you a set to actually try.
They work. The original design and prototype of the ProHUBStands was developed with a Crew Chief/Mechanic who’s won the 24 hrs at Daytona and podiums at 12hrs of Sebring, and a ton of others. They work as intended, promoted and priced. The standard version for track day enthusiasts to Club Racers; ProHUBStands for Club Racers, prep shops and pro teams. They work.
It’s all about measurements that you can repeat precisely, continually.
It’s about the accuracy of the changes you make; the accuracy and repeatability of the baseline values and the repeatability of the changed values. Making an accurate, precisely measured change from an accurate precise baseline that gives you the same, not close, value; the exact repeatable measurements every time. You can’t get that precision at tires. Think of tires like a set of water balloons. They are inherently inaccurate and always changing. That’s why so many serious racers and teams have gotten rid of the tires, gotten rid of their control wheels and measure everything at the hubs on stands, every time. If “you are playing with the big boys” and look for camber values within a tenth of a degree or ride height within a tenth of a millimeter. Stands not tires.
As McRae noted, the camber pivot point of the hub with the wheels and tires in place is further inboard than on the center line of the hub face. It is at a variable point between the wheels backspace edge and the tire’s inner shoulder. It’s near the inside boundary of the contact patch and because the tires vary and squish, so does this point. On the other hand, the centerline of the hub never changes. Again, why would you measure camber at the tire when it’s only repeatable to within a few tenths. The pivot point and camber measurement on stands at the hub is always the same; until you decide to change it.
At the tolerances McCrea describes, the strength of the pad levelers or wheel stands is important. Get good ones, assign them to a specific corner. Get a good pad leveling device. Check the level a lot. If your set up pad is off, everything on it is off.
The critical element with scales is their repeatable accuracy not the number of load cells or strain gauges. Scales registered to be 0.1% accurate used under a 2400 lb car will be within 7.2 ounces per corner, that’s pretty precise. A tire with rubber pick up is more than that.
Specifically for McRae: you trashed my product, ProHUBStands without using them, talking to us, talking to users or even simply seeing them. You pretend to be a professional but that “honest criticism” was pretty amateur and arrogant behavior. Send me your address and Ill ship you a set to actually try.
They work. The original design and prototype of the ProHUBStands was developed with a Crew Chief/Mechanic who’s won the 24 hrs at Daytona and podiums at 12hrs of Sebring, and a ton of others. They work as intended, promoted and priced. The standard version for track day enthusiasts to Club Racers; ProHUBStands for Club Racers, prep shops and pro teams. They work.
12-18-2013, 11:57 AM
#9
There are many schools of thought when it comes to chassis setup. I don’t think there’s one right solution for everyone. For example, an electronic system can compensate for sensor mounting and wheel and tire not being perfect. At the end, your car is not on track with hub stands, but that imperfect wheel/tire combo. Maybe a combination of both is the way to go? It also doesn’t hurt to double check your measurements with a second system, especially at the shop. Obviously, we all want the best solution that works well at the track and not only in the shop.
There may be better ways to do things but calling someone’s setup “utter garbage” is probably not the most prudent thing to say, especially if you have no testing or data to back up your statement.
IMO, the most critical issue is the fundamental understanding of what the car should be doing and the needed changes to get it there. How you go about it might save you time and get you there quicker, but it is not necessarily the ONLY way to do it.
I’m partial to Marty’s products (http://www.mktechnologies.com/index.htm) as I’ve had his equipment for a few years but I wouldn’t be so quick to call someone else’s stuff “utter garbage”.
There may be better ways to do things but calling someone’s setup “utter garbage” is probably not the most prudent thing to say, especially if you have no testing or data to back up your statement.
IMO, the most critical issue is the fundamental understanding of what the car should be doing and the needed changes to get it there. How you go about it might save you time and get you there quicker, but it is not necessarily the ONLY way to do it.
I’m partial to Marty’s products (http://www.mktechnologies.com/index.htm) as I’ve had his equipment for a few years but I wouldn’t be so quick to call someone else’s stuff “utter garbage”.
12-18-2013, 01:17 PM
#10
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I've never used an alignment system on the wheels that doesn't have a compensation for the wheels as part of the procedure. Not that I'm the most experienced, but anything that mounts off the wheels has to have it. If you're talking strings, then you are right that there is no way to compensate for a bent wheel, but that is why people at the top level have setup only wheels.
