Motorcycle Frames: A primer

[MavericK46]

...
Just like the fact that no two apples in a bunch are alike, no two chassis are alike too, even though it may look similar. As explained by several of our experts here before, chassis tuning is almost a black art. Adding the right amount of flex and rigidity to the required parts of the chassis requires countless hours of testing. TVS, by virtue of their track experience would obviously have more expertise in this matter than Bajaj, whose presense in competitive motorsport.

The P220 and the 200 are definitely better because the older gen. pulsars sorta beta tested many factors out for them (chassis behavior and handling being one of them).

Nobody would accuse you of fueling a brandwar for this. It's just a fact of life.

Thanks for the writeup and patiently answering my lame queries Synna
Its articles such as these that make being an xBhpian special !
Here's looking forward to more Synna-Gyaan in the very near future

And for this reason, I somehow feel that not much of "real testing" or R&D has gone into the making of Bajaj Chassis. This I am saying out of pure speculation and not with malice towards anyone.

One has to agree with that explanation Ken da. The main reason being, BAL as a motorcycle manufacturer is the youngest in India.
Both HH and TVS were already creating waves with their CD100s, AX100s when Bajaj was catering to the Scooter and Autorickshaw market. Given the decade plus lead that HH and TVS have had (Let alone the half a centuryish heritage of the Japs alone : Honda, Yamaha), Bajaj seem to have caught up real fast.
At the current rate of development, BAL will definitely be the manufacturer to beat in the not so distant future.
Chassis, Engine, Techno wizardry et all !

P.S : Im sure these are your thoughts on BAL too

[payeng]

Quality Stuff Synn..!!


Chassis tuning is indeed a black art.. the Europeans are probably the best in the business (both for cars and bikes)..

The Twin Spar Frame is already here in the form of the R15.. have started dreaming about a KTM tuned chassis on a "desi" bike (better to outsource perfection than test over variants) in the future.

Question is, how long is the wait going to be..

[payeng]

Hey Maverick,

Any machine that has "Diamond type frame" listed in the spec sheets (The YBX and the Bullets as mentioned before as well as the Hondas and the FZ 16) have a variation of the downtube frame. The difference of course form the cradle frames is that in a diamond frame, the engine is a stressed member. Practically, I haven't found much difference in handling between downtube and diamond framed machines, to be honest.

The only obvious factor would be the weight advantage for the diamond frame.

Another advantage is cost benefit as lesser material is used compared to say a double downtube, double cradle frame.

[rockrider]

my two cents... errr... sites

Honda VTR 1000F Super Hawk

Motorcycle Frame Technology

@Synn: If you feel relevant the first post can be updated.

and this too . found it while googling
The sum of all my synns: Motorcycle frame Primer

[Synn]

my two cents... errr... sites


and this too . found it while googling
The sum of all my synns: Motorcycle frame Primer

Haha, that's where I "backed up" my old thread. It's my now-defunct blog.

Honda VTR 1000F Super Hawk

Motorcycle Frame Technology

@Synn: If you feel relevant the first post can be updated.

If you find any useful info, by all means, post in the thread. It's not just me who can add in the details. Let's make this a collective effort, shall we?

[ken cool]

Great Synn. The Frames are back. The missing photos are back too. And we are back to discussing monocoque vs twin-spar vs trellis. And this probably will change the way a lot of us think and see motorcycles.

[rockrider]

If you find any useful info, by all means, post in the thread. It's not just me who can add in the details. Let's make this a collective effort, shall we?

I mean you can use the link to update few missing link.. for eg.. the Trelli which you have explained beautifully but based on a pic. Should have used few more words.

My attempt to add little more to the discussion

courtesy
Motorcycle Frame Technology

Single cradle frame. The single cradle is the simplest type of motorcycle frame, and looks similar to the first ever motorcycle frames. It is made from steel tubes that surround the engine with a main tube above and other, smaller diameter tubes beneath. If a single cradle becomes double at the exhaust, as frequently occurs, it is referred to as a split single cradle frame. Single cradle frames are usually found in off-road motorcycles.


Double cradle frame. Double cradle frames are descended from single cradle frames. They consist of two cradles that support the engine one either side. Double cradle frames are commonly used in custom motorcycles and simpler road bikes. They offer a good compromise between rigidity, strength and lightness, though they have now been technically surpassed by perimeter frames.




image courtesy My Suzuki GS500E

[Aparajith]

Hey Synn, a doubt. Is there any frame type thats patentd by a manufacturer or is it all open - source (i.e) any manufacturer free to use any type of frame?

[Old Fox]

Great stuff there Synn. Loved it.

Did not see the Earl's Fork mentioned. Loved its straight line stability on the old Rajdoot and also the inbuilt anti-dive. And also its inherent weakness in those 'swing-arm' pivot pins.

Am sure curious to know more about it.

[MavericK46]

IMO, we could expand this very same thread to include discussions on Motorcycle suspension types too.

@OF : If im not mistaken, the earl's fork is a type of front-end suspension. Would it possible to have some gyaan on the Rajdoot's front-end vis-a-vis the telescopic forks of today's machines..?
Especially since those Big-piston forks that the latest Kwackers/Zukis are being shod with are being lauded for the very same anti-dive characteristics...

[ROCKRZ]

wow... nice info...
book marking this page for updates...

[Prabhakar150]

Very informative article. @All, Does the Pulsar 150's frame differs from P200/P220? They almost look same. And whether the chassis got anything to do with stability or control under hard braking?
Please throw some lights on this.

[Prabhakar150]

Very informative article. @All, Does the Pulsar 150's frame differs from P200/P220? They almost look same. And whether the chassis got anything to do with stability or control under hard braking?
Please throw some lights on this.

No one is interested ?

[ROCKRZ]

No one is interested ?

when the bike is braked hard, the suspension dampings play a major role rather than the chasis . on the part of the chassis, the flexibility of the chasis is important (someone do correct me if i am wrong). here, a extremely stiff chassis will wreck a havvoc on the controll of the bike.

[Prabhakar150]

Damping means Are u referring spring action of suspension? How about pulsar's chasis? Is that too stiff or flexible.. When doing 70 above speeds in my pulsar if i have to brake in a panic situation my bike looses its control badly where as my friend's fz takes this so easily. From ur post i believe that the fz's mono suspension also plays major role in control dept. How good bigger pulsars in this dept?