Older chassis fatigue

Hi @rojid. Welcome! To answer your question a little context is needed.  How fast are you,  how fast to you plan to become, and how do you plan to use the car?  I know this sounds like a bit of an odd question because we are all trying to be as fast as we can be.  But it is pertinent here because some of the truly fast drivers have told me that they can feel the difference between a low hour car and a higher hour car.  However most drivers don't seem to be able to tell the difference.  So if you are planning to race and be at the front of a very competitive pack I would say it is more important to get a low hour car.  If you are an average to above average driver, you likely won't notice the difference.  Also, when shopping for cars it is helpful if you can find out the total chassis hours and how fast the previous driver was.  Cars that are driven by the fastest racers tend to take a beating much more than cars that are driven by slower drivers.  So it is common for a two year old car that was race often by a very fast driver to be in much worse condition than an older car that was driven by a slower driver.  

Regarding your question of how the chassis' wear... they tend to get cracks around the shock mounting structure and the engine mount areas.  If it is a higher hour car it is worth having the chassis inspected for cracks.  The good news is that most cracks can be acceptably welded to not impact performance.  

I always recommend that people buy the newest and lowest hour car that they can afford.  It is also worth paying a premium for a car with a documented maintenance history.  It is also advisable to stretch a little further than you are comfortable when initially purchasing the car if it get's you a higher quality car.  I have seen many people try to save a bit up front and then end up paying more over the long run.  

One last piece of advice about shopping for a Radical.  Do you homework so that you know what you want, and then when you find a car that fits your needs / wants move quickly to get it.  High quality cars often sell quickly.  I have worked with a lot of people that took too much time to think about the purchase and end up missing out on good quality cars.  

Also, If you find a car that you like, feel free to email me pictures and information on the car and I would be happy to tell you what I see.  I have seen a lot of cars and can often spot potential issues, and I can give you pointed questions to ask about the car.

@charleyhradicalsportscarregistry-com 

interesting info thank you. 

I purely want to use the car for testing on my own next year. Purely for fun, nothing remotely serious...for now. In terms of my own pace, All i can say is I know i want to have trust in the car when i'm pushing the limits around Copse, so i would be one of those drivers 'beating' on the car -  which is why i want to have confidence in the car that it won't suddenly fall apart at 120mph round a fast corner. I've never owned a race car before so would have a lot to learn re: maintenance.  

It sounds like its probably worth me saving up a bit more and waiting 6 months so i can afford a much newer model. My preferred option is to get a used Formula Renault >2010 but they appear so rarely in the classifieds here in UK, unless i can find some contacts to source me a car. At least every 3-4 months there appears to be a nice looking SR3 RSX for sale so i guess i'll wait. 

this was the one i had in mind. Looked like a bargain given its had a 2021 engine/ECU etc refresh, with the same wheel from the new XX - it was used by the guy who owns AiM. I can see his qualifying performance, in the Radical challenge UK series, difficult to interpret because for whatever reason his car was on a class on its own so no idea if the times are comparable to the fastest drivers. 

I was going to pop down next week and have a look.

https://www.performancetime.co.uk/showroom/p/radical-sr3-rs-2012

@rojid, I wouldn’t have concerns with a 2012.  Performance time is a reputable dealership and I would think Chris would answer all of your questions.  Do you know what the chassis number is for this car?  That is the best way to verify the year.  It is interesting that the bodywork has been updated to gen 3 RSX bodywork.  

If you inspect the car you should not have to be worried abut the car coming apart in a 120 mph corner.  I have never heard of a massive chassis failure in a Radical.  These cars are extremely strong.  Part of the inspection process between races is to inspect the Uprights which is the only structural failure I can think of that could cause a loss of control.

You mentioned that the car has an SR3XX steering wheel, but from the advertisement it says that it has an Aim Formula wheel which is similar but different from the XX steering wheel.

The questions I would ask about this car are:

1) What is the chassis number (to verify the age of the car)

2) How many hours are on the chassis?

3) What repairs have been done to the chassis.

4) Why was the body upgraded? Sometimes people do this because the like the look of the newer style.  Sometimes the old body was worn.  And sometimes it the car was in a crash and required replacement.

@charleyhradicalsportscarregistry-com 

i suspect it's this: https://radicalsportscarregistry.com/radical-sr3-chassis-number-645/

yeh the steering wheel assumption - based on the same advert they've placed on racecarsdirect:

"2021 Engine Refresh At Radical Factory.
2021 Exhaust, Auto Blip, Injectors, PDM System, Latest XX Wiring Loom.
2021 Formula Steering Wheel With Data Screen."

but your'e right, doesn't necessarily mean it's the XX steering wheel. 

thanks for the pointers. 

@charleyhradicalsportscarregistry-com 

i'm going to view the car on Tuesday.

are there any questions to ask about some of the parts?

- for example, im' assuming there'll be some kind of engine log - is any of that data recorded by the ECU?

e.g number of hours used

- is there any way to determine the age of other wearable items somehow, like suspension components?

i can see in the RSX owners manual in section 9.12 a list of parts and approx hours/intervals. I suppose it'd be difficult to determine something visually?

are there any parts i could look at and go 'yup that driveshaft has clearly done more than 10k'

- would you expect a careful SR3 owner to log and document all the servicing done? (section 9.13) i know i certainly would be!

EDIT: just caught up on all the ECU stuff...hopefully he has the cable so i can plug my laptop in and download the data, nice of radical to make the software free. 

@rojid, As you found, yes you can download data from the ECU showing how many hours are on the engine.  When you download the file make sure it doesn't say RDTC at the top.  If it does it means that the battery in the ECU went dead at some point and when this happens it starts the clock over from zero so does not give an accurate accounting of engine hours.  Another trick you can do is to check the hours and mileage on the dash.  There is an arrow button on the dash that allows you to look at other "pages" on the dash.  Keep hitting this button until you get to the page that shows the hours and then again to see the mileage.  This can give you an idea of how many hours and miles are on the chassis.  Be aware that this isn't always accurate because this can be reset by the user and sometimes people reset these to measure different things.  

Also, as mentioned in a previous post, ask how many hours are on the chassis and the engine.  Also ask how he knows this.  Some sources can be verified and some cant.  In the pictures in the Registry the car appeared to have fairly low chassis hours and looked to be in very clean shape and is well optioned.  In the Registry Pictures it appears to not have the rear diffuser in place but this could have been removed when they cleaned the engine for the pictures.  Just make sure it is there.

Another thing that is a good indication of total chassis hours is how worn the steering wheel is.  You will notice where the driver holds the wheel gets smooth and shiny in time. The smoother that is the more time is on the car.

Regarding your question about keeping good records.  I always say that it is worth paying a premium for cars with a well documented maintenance history.  You would think everyone would have this but it isn't as common as you would think.

 Charley gave solid advice. I'd like to add a few things in case anyone else comes in to read this. 

Repairing cracks in a chassis should no necessarily be a deal breaker. Now if they are coming up everywhere and/or uncommon spots then I'd walk away. 

To really look for cracks the right way you need to wire brush any pint off of your welds and go back 2-3 inches on either side. Then come in with either flourescent die and mag it or you could use die penetrant (I like magnafluxing but not everyone has the tools (someone in your area probably does non-destructive testing and they will have the tools)). 

A common mistake is when/if people see the fit line they think it is a Crack. The fit line is where the 2 pieces of metal were originally joined. Now if you are saying "but there should be fusion in there effectively making it all one piece". This is rarely the case unless a full penetration weld is performed and on a tube chassis that isn't possible. Partial pen welds are the best you could do but sometimes not even that gets done. Just two pieces butted up together with no bevel and welded together. In this case you will likely find a parting line. If you aren't sure, if it's a Crack or parting line then excavate the Crack some more with a grinder or burr and see if it follows the perimeter of where the two pieces were joined. If so, likely a parting line. If it crosses the joint perpendicular or at an angle sale more than 10 degrees, probably a Crack. 

Now if you do find cracks, for the love of chocolate DO NOT JUST WELD OVER THEM - EVER! Sorry for the loud words but I've seen it too many times in my career and it always leads to more work down the road. The correct way to deal with them, as I've already mentioned, is they have to be excavated.

What do I mean by that... you have to dig the Crack out until it isn't there any more from end to end. You'd do this by creating a V shape , basically feathering outward more and more as you dig. You'd dig, mag it to look for Crack, if still there repeat until the crack is gone. Then you can come back and weld it up by properly filling the V you just created. 

Why not just weld over? Well the Crack is still there below your new weld. Where there is a Crack there is no strength at all because material isn't joined, pretty straight forward. It is also in the nature of cracks to propagate (grow) so that sub-surface Crack can continue to grow and you can't see it. The worst case is that it grows all the way around and through and now just your new weld is holding thing together which, trust me, will not cut it. 

Cracks will vary in length and depth, light surface cracking is easy to deal with. Cracks all the way through indicate a bad situation. This was either neglected (probably because no one knew) or some very rough short term treatment that severely overloaded the joint. 

I intend to perform an inspection on my chassis before it goes back on track for peace of mind so I will try to post more details. 

@joep, this is great information worthy of a stand alone post.