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maybug Geoff M
Forest Row, East Sussex, UK   GBR
The steering crown wheel has 80 teeth the pinion 24. Therefore ratio 3.33:1
the length of drop arm (centre of crown wheel to drag link rose joint 3" or 75mm)
but more important lock to lock is almost (3/4" short at circumference of s/wheel)1 complete turn of steering wheel. Cheers, Geoff

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chrisenamels Avatar
chrisenamels Silver Member Chris Brown
Llangadog, Carmarthenshire, UK   GBR
Thanks for the information Geoff, about one turn lock to lock is what I'm thinking of aiming for, just enough to do away with some of the twitchiness. I'll be using a chain drive to keep the shaft out of the pedal area, and allow right or left footed braking, so I’ll probably go for a reduction of 2.5 to 3.

Chris

Neto Ernest B
Berlin, Ohio, USA   USA
In reply to # 25682 by maybug The steering crown wheel has 80 teeth the pinion 24. Therefore ratio 3.33:1
the length of drop arm (centre of crown wheel to drag link rose joint 3" or 75mm)
but more important lock to lock is almost (3/4" short at circumference of s/wheel)1 complete turn of steering wheel. Cheers, Geoff

3.33:1 sounds pretty close to the Makita angle grinder gearing. (I need to count the cogs to be exact.) If I'm understanding the rest of your steering configuration correctly (and maybe more importantly, if I understand how a person figures final steering ratios accurately), to get your final ratio I need to ask one more question. That is, what is the length of your idler arms? Are they also 75mm, or are they longer? (If I understand correctly, using idler arms longer than the pitman arm will also reduce the gearing, or, you might also say, raise the ratio (that is, make the first number in your ratio higher than 3.33.)

At any rate, I think that your ratio will greatly improve the steering over the twitchy situation on my friend's go-cart those many years ago. I have it in my notes someplace, but I think I was going to aim for around 1 1/2 turns lock to lock. Would that be way too much steering wheel action?

Edit (2017-07-31 11:58 AM)
Since no one else has responded since my last posts here, I decided to just edit this one, rather than pile on another whole new post.
I checked the number of cogs/teeth on the angle grinder deal, and it has 11 on the small gear, to 36 on the large one. That results in a ratio of 3.2727:1, not quite as low gearing as yours, at 3.3:1. I then checked the pitman arm & idler arm length on the Snapper mower that I'm getting some parts from. The idler arms are 3 1/2", to the 4" pitman arm. That results in an effective final ratio (for the mower, with no steering sector) of 1.1428:1. If I used the same pitman & idler arm lengths, and also used the angle grinder head as a steering sector, that would give a final ratio of 3.74:1. I need to see if anyone here has given data for their pitman & idler arm lengths.



Edited 2 time(s). Last edit at 2017-07-31 10:59 AM by Neto.

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Neto Ernest B
Berlin, Ohio, USA   USA
In reply to # 25683 by chrisenamels Thanks for the information Geoff, about one turn lock to lock is what I'm thinking of aiming for, just enough to do away with some of the twitchiness. I'll be using a chain drive to keep the shaft out of the pedal area, and allow right or left footed braking, so I’ll probably go for a reduction of 2.5 to 3.

Chris

I also need to avoid the common steering shaft configuration, but not only to keep it out of the floorboard area, but because I plan to place the engine up front. Thinking of using cowl steering, so I need some sort of steering sector. I looked at some golf carts, but they are still pretty heavy looking.

maybug Geoff M
Forest Row, East Sussex, UK   GBR
To get 1 turn lock to lock , measure distance that the tie rod between wheel arms has to travel, make drop arm from "steering box" a length that gives this distance when given 1 rotation. The distance from wheel centre to cross steering joint will also be a factor.

When I had a Dellow trials car the steering was modified to 1.25:1 by increasing the length of the Ford steering box drop arm.


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Neto Ernest B
Berlin, Ohio, USA   USA
In reply to # 25682 by maybug The steering crown wheel has 80 teeth the pinion 24. Therefore ratio 3.33:1
the length of drop arm (centre of crown wheel to drag link rose joint 3" or 75mm)
but more important lock to lock is almost (3/4" short at circumference of s/wheel)1 complete turn of steering wheel. Cheers, Geoff

On the steering, what is the shaft diameter of the hand drill mechanism you are using as the steering sector? I've seen all sizes, from the small hand operated ones up to the larger breast drills. I have an incomplete hand held one one that was in a box of stuff I got years ago at an auction. The gearing is 56 to 15, or 3.73:1, so the shaft of this one is probably smaller than what you have. (The shaft of mine here appears to be 7/16" diameter, or about 7 mm. But I think it is bent slightly some place, because it doesn't turn evenly & freely. I don't know why I didn't think more about it when you mentioned this earlier - I just dug this one out this morning. My father-in-law has at least one of the larger ones; I should count the teeth on that when I'm out at his shop sometime.)

[Edit: I just thought to check the arm length, and this one is obviously smaller, with a length of a bit less than 2 1/4".]



Edited 1 time(s). Last edit at 2017-08-02 06:29 AM by Neto.

maybug Geoff M
Forest Row, East Sussex, UK   GBR
The pinion shaft is 3/8" or 10mm I have cut a thread on this and an internal thread in the steering column with lock nut , and will secure with grub screws.
I drove it up the drive today, steering felt very direct and a bit skitty, but the front of kart is very light? Big smile! Cheers, Geoff

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DOMIT William Smith
Fort Worth, Texas, USA   USA
Chain and sprockets for steering reduction? Just a thought.

maybug Geoff M
Forest Row, East Sussex, UK   GBR
My thoughts are keep it simple. I had the drill so I've tried it. All rear engine cyclekarts,
especially with 1 wheel drive or solid axle, must understeer, like a chain drive Fraser Nash. Cheers, Geoff

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Neto Ernest B
Berlin, Ohio, USA   USA
In reply to # 25773 by maybug The pinion shaft is 3/8" or 10mm I have cut a thread on this and an internal thread in the steering column with lock nut , and will secure with grub screws.
I drove it up the drive today, steering felt very direct and a bit skitty, but the front of kart is very light? Big smile! Cheers, Geoff

I am assuming that "skitty steering" means that it is really touchy, or sensitive. I have been looking for some simple steering sector (or something to use for one) that will give me a ratio of around 8:1 up to 10:1 at the slowest, or least responsive. I know that is way over the ratio most use, but I am also planning on putting the engine up front, and pretty far forward, too. (So I will have a good deal more weight up there than most.) The angle grinder 90* gear box I have is still only around 3.27:1. The shaft on that deal, by the way, is also 3/8". (This is the part where the armature was. I was able to force it off on a press. Or maybe I used a hammer. I don't remember now.) Do you think the shaft on yours is going to be strong enough? So far I like the angle grinder deal best, but the hand saw I have is smaller than yours, so not as beefy.

gearguy Charles Schultz
Oil City, Pennsylvania, USA   USA
Have you considered making up the rest of the reduction ratio you want with a chain drive after the bevel set? There have been cowl drive set-ups shown here that had chain in them and it wouldn't be hard to package it around your front mounted motor.

Neto Ernest B
Berlin, Ohio, USA   USA
In reply to # 25785 by gearguy Have you considered making up the rest of the reduction ratio you want with a chain drive after the bevel set? There have been cowl drive set-ups shown here that had chain in them and it wouldn't be hard to package it around your front mounted motor.

I think that would work, but I was hoping to avoid that extra weight. The golfcart steering sector I looked at was a cast aluminum case, but I don't know what the ratio was, or if it would have to be reversed yet. It was still mounted, so I also couldn't weigh it. (They had already taken some parts off of it, but still just wanted to sell the whole deal for $500.00. Maybe could have also used some other parts as well, but those carts are built pretty heavy.)

This was on a car (ratrod), but I've read where someone used a chain drive in their steering, and he said that no matter how tight he got the chain, there was still slack. (But a cyclekart would have that sort of speed, so probably not an issue. Weight is the main deal, because I'm already adding extra weight with the engine up front.)

Torro123 Avatar
Torro123 René Wesselius
Amsterdam, NH, Netherlands   NLD
Ernest on my build i use a chain/sprocket,ratio 1:3 and use a tensioner to reduce slack,with front engine steering is good enough
Picture showing is first set-up 1:1 ratio no tensioner



Edited 1 time(s). Last edit at 2017-08-04 10:57 AM by Torro123.


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maybug Geoff M
Forest Row, East Sussex, UK   GBR
A couple of photos of the wings (fenders) under construction, very time consuming and probably very heavy?


Attachments:
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CmdBentaxle Avatar
CmdBentaxle Silver Member Dave D
Federal Way, Washington, USA   USA
1950 CycleKart Italian "1950 Ferrari 166 F2"
Like building a entire second body.
But there's no substitute for the authenticity you'll acheive.
I really appreciate builders who tackle the challenging
coachwork.

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