CHOP CULT HOME
Email Password
Search
  1. #1
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    May 2018
    Posts
    740

    Default Preferences of 16" versus 21" on springers

    Besides looking cool as hell, are there any advantages of running a 16" on the front of a rigid frame/springer (running the same size tire as on the rear)?
    I've ran a 21" for north of 30 years, never ran a 16 on the front of anything. Seems like the ride might be better with a 16 versus the 21, but I just don't know and I'm curious... I'm contemplating a change this winter and would love to hear any thoughts or opinions on it.

  2. #2

    Default

    There is a difference. Been on a 16 up front rigid/ springer for last few years. Never had a 21 on but have riden a couple of bikes that did. 16 does feel a little more sure footed in the turns.

  3. #3
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    May 2018
    Posts
    740

    Default

    Thanks for that, I'm going to do it.

  4. #4
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2012
    Posts
    1,007

    Default

    whats missing here is a discussion about rake, frame geometry and how tire & wheel sizes impact it.

    First, the easy part. 21"s on the front on a chop tend to be a skinny medium to high profile tire, (In the old days think Avon Speedmaster ) which tend to be a tiny contact patch, poor wet weather-rain tires, and only really good in a straight line. (To be fair, No one is carving canyons and racing a chopper) RM1 rim widths..

    Now, a 16 tends to be fatter, RM3 rim widths Tires can vary between low profile to insanely large high profiles. As well as possibly having clearance issues. All of that can add up to a lot of rolling resistance however on certain style bikes, a fat front and rear 16" can look cool

    But more complicated is, how is the geometry already? Done the calculations for rake and trail? I have seen tiny and small front tires on springers and they generally dont do well. Scrub instead of turn, But often times, I start with a defined frame height and strive to keep it level, then play with front ends, lengths and rake and trail to get the ideal ratio for handling.

    Get it right, and bikes tracks like a dream, corners well, and no flop. Get it wrong its scary and dangerous to ride, exhausting and can get you hurt or killed since a bike thats out of control can be a death sentence.

    https://chopperbuildershandbook.com/rake.html

    Before you make any changes do the math for your front end. THEN order parts. & Forget that Norcal high front end stupidity. Looks like Sh*t, and handles even worse.
    Click image for larger version. 

Name:	Norcalimages.jpg 
Views:	33 
Size:	13.1 KB 
ID:	106323

    Click image for larger version. 

Name:	Rake and Trail Table from Bradley.jpg 
Views:	9 
Size:	103.3 KB 
ID:	106324

    So, Not a huge number on the center of axle to the bottom of tire contact patch but it raises or lowers enough it DOES matter, even changing the aspect ratio of the tire, or height. profile, however you want to call it.

    Click image for larger version. 

Name:	RakeSECTION-2_img_18.jpg 
Views:	3 
Size:	47.2 KB 
ID:	106325
    Last edited by Dougtheinternetannoyance123; 11-01-2021 at 10:44 PM.

  5. #5
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    May 2018
    Posts
    740

    Default

    Quote Originally Posted by Dougtheinternetannoyance123 View Post
    whats missing here is a discussion about rake, frame geometry and how tire & wheel sizes impact it.

    & Forget that Norcal high front end stupidity. Looks like Sh*t, and handles even worse.
    Thanks for your reply... Rake is 33 degrees. Springer is stock length. Tire will be MT90-16, front and back, on 3.5 rims.

    As for you Norcal statement... Agreed, X10. I fucking hate that shit. Those came about in the early days because people who didn't know what they were doing, and/or were too lazy to do it right, just stuck long front ends on a stock frame, jacking the front of the frame up in the air. Even dangerous in my opinion. The closer to parallel the bottom of the frame is to the ground, the better I like it.

  6. #6
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2012
    Posts
    1,007

    Default

    Somebody on here about 2 years ago was playing around with software to do online mockups and frame geometry which I thought was great, I tried years back and never could get the Algorithm math formulas right. Haha,, But in the old Jammer chopper guide they had little drawings you cut out and glued to a sheet of paper to do a mock up. Elmers glue mock up! Chopper arts and crafts!

    Had frames, wheels, tanks and seats,,, use an Xacto knife and lay that out to see what it will look like,. Long before software and computers.

    Anyrate, if that guy who was doing the software is still around, I have some bare NOS Cherry aftermarket frames I can photograph so he can do his CAD/CAM wizardry. I meant to do it back then and life got in the way, but I have access to the frames as I unburied them.

    As to NorCal look? I get trying ideas to look cool, and in the past a few people yelled at me for sayin it, But all were young bucks, and you dont hear old geezers sayin that stuff.

    Click image for larger version. 

Name:	Norcalchopper2427248_362873514_n.jpg 
Views:	5 
Size:	137.8 KB 
ID:	106327

  7. #7
    Sugarcubes
    Guest

    Default

    I have a stock length springer and run dual 16x3 rims on Avon Mk2 5.00 x 16 tyres in the winter months and change out for a 21 x 3" with Avon speedmaster in dryer summer months.

    The 16 up front gives me a bit more surface area in the slippy colder conditions but the steering does feel heavier as if I need to slightly shove it around corners more. It also massively helps absorb imperfections and potholes in the road should I accidently come into contact.

    The 21 seems to handle a lot nicer in the corners and I prefer it in the summer when I am more likely to be up in the hills.

Share This



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in