When you look under your fender you see that the available real estate has been encroached by some large protruding fasteners.  You can remove some of them and replace them with stainless steel flat head and pan head socket type fasteners from:


www.boltdepot.com/product.aspx?cc=25&cs=82&cm=19&cd=1318

The list of possible replacement fasteners goes like this:

 Item # C
 Product #6698
 Metric socket flat head screws, Stainless A-2,   8mm x 1.25 x 16mm
 Quantity: 4 pieces
 Price: $0.54
 Subtotal: $2.16

 Item # B
 Product #6702
 Metric socket flat head screws, Stainless A-2,   8mm x 1.25 x 35mm
 Quantity: 4 pieces
 Price: $0.73
 Subtotal: $2.92

 Item #A
 Product #6657
 Metric socket button head screws, Stainless A-2,  8mm x 1.25 x 25mm
 Quantity: 4 pieces
 Price: $0.96
 Subtotal: $3.84

 Item #D  Welded Nut
 Shorten slightly with 4" grinder
 Overmold (blend a hump) with JB Weld Epoxy
 Paint with silver touch up paint

 Item #E  (not shown) Mounting bolt for Right Buddy Peg
 Shorten slightly with 4" grinder
 Paint with black touch up paint

You will need to buy a HSS countersink to countersink the flat headed screws to be nearly flush to the sheet metal that they will retain.  Close to flush, but not completely flush.  You do want some metal there to clamp up to, right?

Go slowly here == making the countersink too deep & large means you won't hold the sheet metal in place and that is a classic "bad thing" when trying to hold stuff together with flat headed fasteners.

The main fender mounting bolts get replaced with shallow pan head fasteners instead of flat heads.  Why pan heads?  You got these protector bumps in the sheet metal and all you really need to do is get shorter than the bumps.  Pan heads are stronger than flat heads and the fender is a structural element that sees strong vertical vibrational forces and potential tire/fender impact forces.  It needs more fastener strength than the horizontal mounted gingerbread stuff that we flat headed for width clearance.  

Note that the item #A fender mounting holes here aren't simple holes, they are slots.  If you need to shift the fender a bit to avoid a rub this is the time to do it.

Now, do you REALLY need to do all this removal and replacement of fasteners?  It depends on how big your oversize tire is and where it runs when installed on your rim.  

If you were rational and picked a 150/80 bike tire you likely won't have to do much at all.  If you were moderate and picked a 145-15 VW tire you wouldn't have to do near as much.  If you plan to put a 175/65R15 Continental on as your next experimental tire after you do yourself a chain conversion -- heck, you may need to flush mount everything you can possibly flush mount.

As always, this information is for theoretical discussion only -- nobody is actually ever going to do any of this silly stuff.  We all got better sense that that, naturally.  

Oldfeller

PS   Buy the type of countersink with a single straight cutting edge that is easily resharpened with a standard bench grinder -- you will likely have to resharpen your countersink edge at least once while removing all that metal.

Hay
These dard side tires or nothing new. what do you think the original bikes had?  
I have  VW. tire on the back of mine now and love it.  its a Mitchelin 145xr/15 from Coker Tire.  I'll send a picture if i can put it together.  The first thing I did was lay the bike down in the grass all the way to the crash bar.  Its imposible to make it get onto the sidewall.  I've got about 1,000 miles on it now and the rearend drift is so predicable and sweet I cant help do curves faster than i should, its plain FUN.
Has anybody else done this yet  get back me

Here is a fully functional 165-15 FAT TIRE mounted on a stock Savage bagger using the standard drive belt arrangement.  Extra clearance for the big tire was created in the fender well by removing the protruding bolt heads that Suzuki uses to clutter up the fender well on both sides.

There is ample clearance to the top.  There is lots of clearance to the left side.  There is clearance to the belt (but not much).  There is clearance to the belt guard (which is easily told to move over using a flat crowbar,  BTW).

Clearance to the right is very slim to none and needs some more work.  I will be changing the axle spacers to shift the tire over to the left to become more centered in the fender well.  The rear pulley (and the small belt clearance) will move along with the tire as the tire shifts, but the belt guard will likely require more adjusting with the flat crowbar after the shift is made.

So far handling on the fatter tire is not drastically different.  You can still drag a peg if you want to and braking ability in the wet has not declined to any noticeable degree.  You can skid the back tire if you get on the brakes really really hard (but you could do that with the stock IRC tire, too).

Best running pressure seems to be between 22 and 27 pounds of air.  Below 22 and things begin to feel mushy.  Get up to 27 and hard edges begin to be felt when leaning the bike over in a turn.

Does it feel different?   Yes, there is a whole lot more tire back there now and I am still learning how to use it to best advantage.  Taking a steep bank turn and hitting the gas as you exit the turn seems to make the tire want to dig in deeper which is new to me.  

Since I am managing my air pressure in the sweet zone I don't have the hard edges that so many have complained about.  I keep adjusting the pressure but the sweet zone is becoming more defined for me and seems to be heading towards 24-25 pounds.

I would say this mod is certainly doable, but I would also say is not for a beginner rider as you have to use good judgment as you make any modifications to the handling characteristics of your ride.

Your butt is 100% riding on your good judgment here, you know.  There is serious experimentation going on at the adjusting/riding stages now and I won't take the bike out into heavy street traffic until I get more miles on her and know more about how the new tire reacts to various hard braking and harsh movement scenarios.  

Oldfeller

Now, how do you adjust the centering of a wheel assembly inside a fender well?   Especially if you need to shift the tire from right of center (Suzuki standard location) over to the left to get more room for a good bit bigger tire?

Answer, get 3 each of a 17mm I.D. plated steel washer and stack them all up and measure them as a total.  Cut the same total amount off the left side axle spacer (the fat one with the bearing seal riding on it that goes on the outside of the drive pulley).

Now you can move your wheel assembly around by a single washer's distance as you put the varying count of washers on the side that needs to be "thicker" to make the position of the tire be where you want it to be.  The total width of spacers and all 3 washers always remains the same, but the tire assembly moves back and forth at will by "one washer" increments.

That's how you fine tune your rear end "left to right" to make it perfect for whatever fat tire you have mounted on her this time around.

A point to be aware of if you have to get extreme with the tire lateral motion --- as you move left you decrease the amount of the female engagement of the brake drum assembly slot on to the male portion on the swing arm rib.  You can only go so far before you promote a divorce on these critical parts, so if you see the engagement getting a mite slim you might want to back off some on your tire shift.  

Your choices to go further left will need to include an extender plate on the brake drum assembly to reach out the slot to find the rib on the swing arm.  When you go to make such a thing, be aware that a 10-24 flat head socket screw will just span the gap on the inside of the hollow part of the casting such that the threads will sink in on both sides giving you more length of engagement.  The head of a 10-24 flat head just fits flush to the edge of the slot too.





So now you have all the tricks needed to fit a 165-15 OR BIGGER tire.  You can center your tire in the cleaned out fender well and you have just a tiny bit of clearance on all sides.  And what is neat is you didn't have to put a chain drive conversion on your Savage to do the mod either.

Oldfeller

8) Oldfellar ... I'm really diggin your Darkside Tire mod on the LS! Gutsy, rebellious and slightly obnoxious! Way cool on all counts!  8)

Oldfeller - when are you going to add the little golden eyed, sabre clawed banshee to the mix?

What good is a squirrel bike without a mascot!?  

Hey Oldfeller2, I'll be trying the 135 x 15 when the time comes.  I have a 17/43 chain conversion and don't need the extra height or the extra width on the already too skinny rim.  The strange thing is, I've got 3500 miles on the stock IRC and it's showing no signs of wear yet...

Perplexing!

Oh well, guess I'll have to rack up miles faster!