I know there are a lot of threads in the forum about it, and I’ve read a lot of them, but I need to understand better what can be right for me.
I have an IPK (Praga Dragon Evo) chassis and need to change the seat. I do the Italian club regional championship, category X30, which already requires a lot of money, and I can’t afford to have several seats to adapt the chassis to the track condition from time to time. I’m trying to figure out which seat to buy that will work for all conditions.
Doing races, I need a seat that works well with a rubber and high grip track and with air temperatures ranging from 20 to 35 ° Celsius. I’m 175 cm tall, weigh 78 kg, and my riding style requires a very stable rear, not very slippery, almost understeer. As a basis I use a medium/soft or medium/hard axle both cut to 1000mm, standard height both front and rear, magnesium hubs both front and rear (92mm rear and 71mm front) and Douglas rims, the rest of the setup we adapt it depending on the tracks and the conditions.
My questions are:
What stiffness of the seat?
What inclination?
What height from the ground?
What about the struts?
Last but not least, which brand to choose?
My current position is this but with the new seat I would like to be with my shoulders slightly more pushed back, what do you think about it?
Based on the class and your setup, I’d start with an IPK regular racing seat and aim for a weight distribution of 42-43% on the front and a seat bottom 5 mm above the bottom of the frame rails.
Kart shop, if they have 4 pt scale. Tracks/clubs will have one for post heat weighing, so you could always take your rig to an event & ask to weigh it.
Before you start messing with different seats, verifying your weight distribution is correct with a stock seat should be first priority.
Seat placement and weight distribution is one of the most important aspects of kart tuning. It’s part of the foundation of tuning. If it isn’t right, nothing you do with chassis adjustments will be optimized.
Yes, in any case I have to change the seat, so I’m trying to figure out the solution for an optimal setup.
Now I have understand how to measure and adjust front and rear balance, but what about side balance? I mean, the right side is heavier because of the engine, so it’s acceptable to have more weight on the right side or should I move the seat further to the left to have the same (or similar) weight between right and left?
If you look at pretty much any kart, the seat is slightly angled, putting more weight to the opposite side from the injun.
Seat struts I’d say just go out and try with - without. You can feel the difference immediately at least I could.
And why analog scales you ask? Because the digital ones self shut off once they’re stable to save batteries. You need to get someone to race around the kart lifting each wheel off and back onto the scale and try to do that with all four before the first shuts off. Ask me how I know hahaha
50/50 side to side if possible. Seat is offset to compensate for the engine, and it’s normal to add weight to the left side as well.
Seat struts - run at least one per side as a baseline.
I would honestly just run the stock seat that IPK recommends. Seat tuning is a more advanced method of working with the kart, and unless you’re competing at the top level it’s likely not necessary to try and pick out a specific seat for your conditions. I would focus on getting the stock seat in the right place. If you are at the level where you haven’t scaled your kart yet and aren’t sure on your weight distribution, tuning with the seat is probably not a priority yet.
Otherwise, Richard’s link to Tillett’s website can be a good resource if you want to read about different seats. The Tillett T11 is probably the most popular model and works in a variety of conditions. It’s the baseline seat for many applications. At your height the standard seat should be just fine. Charles’ advice on weight percentages and baseline height are pretty standard and spot-on.
I have checked the balance with the 4 scales and with the new seat (Tillett T11T). It seems that I have 40% front and 60% rear, I think it’s ok. The problem is that I have more weight on the right: 33 kg front right vs 31 kg front left and 50 kg rear right vs 46 kg rear left. We can’t do better because the seat is already more lefted than normal.
Do you think that this weight difference between left and right will affect the kart balance and the laptime, especially in fast corners?
40% front is a bit low. I would be moving the seat forward a bit.
That isn’t a huge difference in side-to-side weight balance. Do you have extra ballast to move around to fix that difference?
And just to confirm, were the scales level? I only ask because if both right side readings are heavy, it could be slightly un-level with that side a bit low.
Unfortunately I don’t have ballast, I’m 5 kg over the minimum weight only with kart and myself we have all light components and I think we don’t have any components anymore to move around
I honestly have not thought about this at all, do you think it could be due to this a little difference in weight?
Any time you are weighing something with multiple scales, you first need to confirm it is level in every direction or one end will be heavy. Until it’s level, any weighing you do is meaningless.
I’ve just checked the scales and again the kart + driver weight. They are perfectly leveled, so the weight difference between left and right is real. Do you think it’s ok to race like this? If it’s ok, I will only move the seat a little bit forward
Not sure if this helps, but a couple of years ago when needed a new seat, I emailed the guys at IMAF (I think they are near Pescara) and asked for all the specifics. They sent me a reco on seat and chart on exactly where to put it. It worked perfectly.
we have all light components and I think we don’t have any components anymore to move around