The time has finally come to upgrade my kart frame after over two years of driving an older frame. The most popular distributor in my country is CRG, so I am quite settled on the brand. What I would like to get some feedback on is the model of the frame. From what I’ve seen, the most popular ones are the KT2 and Heron. According to the distributor, and even after asking the CRG team on their Facebook, the KT2 has more grip on the front, while the Heron has more grip on the back. Unfortunately, I’m not able to drive either frame back to back, as the would be ideal.
I’m not sure if anyone on these forums has driven both of these frames or has experience with them. It seems like OTK karts are more popular, and I can’t find much information on CRG frames. I feel that this is quite a big decision to make, so some advice would be much appreciated!
What class will you be running, and on what tire? That should help to inform your decision, as each chassis will be better suited to certain conditions.
If it’s any help I run X30 master so 170kg weight. Komet K1H, though I’ve run a race on K1M because Covid interrupted tyre supply. K1M is like chewing gum! Also club races on Mojo D5.
I haven’t tried Heron but I’d be inclined to agree about KT2 being more grippy at the front, actually i found it a bit TOO grippy - felt like it was snapping into turns when I first started driving it. Soon got it dialed out though - changed the front track, reduced caster by a serration and a seat strut on each side to balance the rear.
I love the way it drives and the way it responds predictably to set up changes.
Thanks for the replies and sorry for the delay in replying. I’m currently running X30 with the new K2H tires (much better than the older K1H, even faster than a K1M with the same durability of the K1M).
@Richard_Jacques glad to hear that as I do prefer a ‘pointier’ chassis! Two small questions:
Have you ever had a condition where you couldn’t tune the chassis to some particular conditions? With the Heron being particularly grippy at the back, I think it’s quite likely to end up in a situation where you can’t remove enough grip. With the KT2 being a more conventional chassis, I think this might be less of an issue.
How does the performance compare to OTK frames? They seem to be far more popular in the big races (such as FIA), but I’m not sure if that’s down to availability or if the frame has more ‘potential’.
Hi Zain – I’ve been driving CRG’s and Zanardi’s for about 12 years and currently club race a Zanardi KZ2 with a Rotax Evo. As I am slipping into my dotage (hence, Old Guy), I thought I’d try a VLR 100 with a new CRG KT2 chassis. I have never had so much fun driving a kart. It is alive and crisp, and I’m taking some turns faster in it than in my KZ2/Rotax. I’ve given some of my faster friends a session behind the wheel and they all come off the track with the same high praise. As I understand it, OTK frames are much softer than CRG’s, so that you tune them differently (e.g., OTK’s normally have front – and often – rear bars added, while it is unusual for CRG’s to use these supplements). By the way, a respected racer and team owner, Ron White, set up my KT2 – if you buy one, I’d be pleased to give you the “specs” on how he did it.
Never not been able to tune the KT2, just to note according to CRG ME who I drive with, the Heron is designed for and aimed at shifter category - which would explain the rear grip bias.
KT2 / X30 I find responds well and more important predictably when you change the set up.
Do share, I’d be interested to try it. May I be so bold also as to ask what is your driver/kart weight? I normally weigh in around 176kg, 6 over my class minimum.
Richard – First as to weight, we use the Challenge of the Americas as our “standard” for club racing in Tucson, so kart and driver must be at least 380 lbs. at pit in for the 100cc TAG class (I’m using a VLR 100); I’m 5’8" and I’ve had to add 18 lbs. of lead to make weight. Ron used stock CRG components, except for the seat which is a Tillet T11t. He added a single seat strut on each side. I had him place the seat, so I do not know what measurement he used; I just know it must be a set distance from some reference point as he did NOT use my measurements (height, inseam, whatever) in any way. He put the rear tires out at 139.5 cm (54.92 inches). I did have him cut the CRG axle to 1000cm instead of the stock length of 1020. The 3rd bearing has been taken out and the rear bumper is loose vertically. He used 2 1/2 spacers out each side for the front width, 0 castor on the top sniper plate, 2mm negative camber and 2mm positive toe each side sitting on the kart stand. I experimented with a nylon front torsion bar but found I was faster (and the kart felt more lively) without it.
I’m typing this from home and my kart is at the track, so I cannot do any measurements to help with seat positioning. If this is important to you, I will be at the track mid-week to wrench for our upcoming club race and I can get a couple dimensions for seat location. Also, Ron set the ackerman, so I could get what holes he selected on the steering column and the spindle and forward that info as well.
Cheers
That’s pretty much recommended baseline set up, CRG set mine the same except shortening the axle. I moved front track in 1/2 spacer to dial out a bit of entry oversteer and set caster 1 serration to negative (neutral is +10 deg) to help it roll smoothly out of the turns. One seat strut either side I have, third bearing isn’t removed but it’s loose - just kept in its place with a loose cable tie.
I’m still a bit confused when people call out “0 castor” or “stand it up”. I agree that the king pin on a kart leans back so as to create positive castor (I did not know it was precisely 10 degrees). However, when folks say to “stand it up”, how many lines are showing towards the front of the kart on the sniper castor/camber base that sits under the castor/camber top? Does the top cover all lines of the base?
Never come across ‘stand it up’ and of course a kart never runs 0/zero caster.
Caster is built into the chassis by the position of the 'C ’ bracket on manufacture.
@Richard_Jacques tells us above that the built in caster angle on his CRG is 10 degrees. ie The kingpin leans backwards at 10 degrees to the vertical when the caster adjustment is in its central ( neutral) position.
The Sniper adjusters (good pics at www.sniperamericas.com) allow for caster adjustment of around 3 degrees each way from the neutral setting in 1 degree steps. ie 7 to 13 degrees of caster.
So in the neutral position 1 line is just showing on the Sniper base to the front of the kart. 1line to the rear of the kart. The ‘top’ is central fore and aft on the’ base’ and you have around 10 degrees caster.
For max. caster the ‘top’ is moved backwards over the ’ base’, 4 lines visible on ’ base’ to front of the kart none to back, 13 degrees caster.
Min. caster 4 lines visible to back none to front, 7 degrees caster.