gearbox question... r&p vs gears??

[folkevogn]

just wondering.....there is alot of different R/P and gears out on the market


f.ex if you have a 3.88 r&p with a 4.25 1st as one combo and another combo with 4.12 r&p and 4.11 1st....(keep in mind that the numbers are just randomly picked)
is there a difference in where the forces is applied on this two combos
And if so, is it better to increase the ratio of the r&p to f.ex 4.86 with a smaller ratio on 1st, or vice versa?
I understand that you can buy stronger parts, but thats not the clue..

If both r&p`s could handle the same amount of tension and the gears would handle the same amount of tension...witch one would break first?
Lets leave tire grip and the rest out of the equation....

Feel free to be scientific if you want too, and find it necessary..

[richie]

just wondering.....there is alot of different R/P and gears out on the market


If both r&p`s could handle the same amount of tension and the gears would handle the same amount of tension...witch one would break first?
Lets leave tire grip and the rest out of the equation....

If your summary was true then neither,they would both last the same.
But the 4.12 has weaker teeth due to more teeth in the same circumference as the 3.875.
The shorter the first gear the easier it is to get the car to move initially,hence why people use 4.11 and higher numbers on a heavy car or on a small engine without the torque to help overcome the weight.
cheers richie,uk

[folkevogn]

thanks Richie...

I see your point with the heavy cars and small engines, its very obvious(and after giving it a tought,so was the answer for my initial question on forces  )

But you pointed out one thing....the 4.12 is weaker because of more teeth in the same circumference
Correct me if I`m wrong, but what your saying is that if you could use a 3.5 r&p(with a "bigger" 1st) it would be stronger than a 3.78(with a smaller 1st)??
Or will the "bigger" 1st then be weaker and you wouldn`t gain strenght?

[richie]

Less teeth = bigger teeth=stronger,thats the way i see it anyway,the 3.44 r&p should be stronger still but i am unsure if the material is as good a quality as the origional german R&P

Or bigger circumference[bus box or mendeola] =stronger teeth

cheers richie,uk

[Roman]

Less teeth = bigger teeth=stronger

cheers richie,uk

This is a strong one:
 

[richie]

Less teeth = bigger teeth=stronger

cheers richie,uk

This is a strong one:
 

His breath???

Looks a little like one of my old type 1 gears

cheers richie,uk

[folkevogn]

hehe nice one Roman

@richie...is the 3.44 a aftermarket part. If so, why didnt they make it as strong or stronger than the original ones, I would guess they made them for racing purposes(wild guess)
I cant see any reason why people shouldn`t use them if their stronger(given that they are the same quality as the original ones)
The cost might be one of the reasons, but those mendeola tranny`s aren`t eccactly cheap either
And either way, mendeola and bustranny`s aint an option for me

[richie]

hehe nice one Roman

@richie...is the 3.44 a aftermarket part. If so, why didnt they make it as strong or stronger than the original ones, I would guess they made them for racing purposes(wild guess)

They may well be as strong or stronger,I personally havent tried one,they seem more suited to a real light car[kit car. ie fake 356 etc] due to the taller gearing

I cant see any reason why people shouldn`t use them if their stronger(given that they are the same quality as the original ones)

The quality is unknown as they are aftermarket[richmond gears I think] and i havent seen one tested to destruction.You want to try???

cheers richie,uk

[folkevogn]

Hmmm...I might wanna try it if I can find some info about it why not try something different, I might learn from it, or not

You probably saw this coming .....
my next question is if I choose a 3.44 r&p and then have to choose a taller 1st to make up for the "smaller" r&p. Lets say I choose a 4.12 1st instead of a 3.78 1st(if I had choosen 3.785r&p)
If the 1st gears where made of the same quality of steel, would they be equaly strong?(do they have the same amount of teeth and different circumference, witch i turn will make one of them stronger than the other?)I know 1st consists of mainshaft gear and pinionshaft gear...

Thanks for the replies...

Folke Vogn